diff --git a/src/charset.c b/src/charset.c
index 21fb4e5..90cf06c 100644
--- a/src/charset.c
+++ b/src/charset.c
@@ -463,41 +463,42 @@
 	    if (enc_utf8)
 	    {
 		int	c = utf_ptr2char(STR_PTR(i));
-		int	ol = utf_ptr2len(STR_PTR(i));
+		int	olen = utf_ptr2len(STR_PTR(i));
 		int	lc = utf_tolower(c);
 
 		/* Only replace the character when it is not an invalid
 		 * sequence (ASCII character or more than one byte) and
 		 * utf_tolower() doesn't return the original character. */
-		if ((c < 0x80 || ol > 1) && c != lc)
+		if ((c < 0x80 || olen > 1) && c != lc)
 		{
-		    int	    nl = utf_char2len(lc);
+		    int	    nlen = utf_char2len(lc);
 
 		    /* If the byte length changes need to shift the following
 		     * characters forward or backward. */
-		    if (ol != nl)
+		    if (olen != nlen)
 		    {
-			if (nl > ol)
+			if (nlen > olen)
 			{
-			    if (buf == NULL ? ga_grow(&ga, nl - ol + 1) == FAIL
-						    : len + nl - ol >= buflen)
+			    if (buf == NULL
+				    ? ga_grow(&ga, nlen - olen + 1) == FAIL
+				    : len + nlen - olen >= buflen)
 			    {
 				/* out of memory, keep old char */
 				lc = c;
-				nl = ol;
+				nlen = olen;
 			    }
 			}
-			if (ol != nl)
+			if (olen != nlen)
 			{
 			    if (buf == NULL)
 			    {
-				STRMOVE(GA_PTR(i) + nl, GA_PTR(i) + ol);
-				ga.ga_len += nl - ol;
+				STRMOVE(GA_PTR(i) + nlen, GA_PTR(i) + olen);
+				ga.ga_len += nlen - olen;
 			    }
 			    else
 			    {
-				STRMOVE(buf + i + nl, buf + i + ol);
-				len += nl - ol;
+				STRMOVE(buf + i + nlen, buf + i + olen);
+				len += nlen - olen;
 			    }
 			}
 		    }
diff --git a/src/digraph.c b/src/digraph.c
index ed22b34..fc29ac7 100644
--- a/src/digraph.c
+++ b/src/digraph.c
@@ -2080,13 +2080,13 @@
 /*
  * Lookup the pair "char1", "char2" in the digraph tables.
  * If no match, return "char2".
- * If "meta" is TRUE and "char1" is a space, return "char2" | 0x80.
+ * If "meta_char" is TRUE and "char1" is a space, return "char2" | 0x80.
  */
     static int
-getexactdigraph(char1, char2, meta)
+getexactdigraph(char1, char2, meta_char)
     int		char1;
     int		char2;
-    int		meta;
+    int		meta_char;
 {
     int		i;
     int		retval = 0;
@@ -2159,7 +2159,7 @@
 
     if (retval == 0)		/* digraph deleted or not found */
     {
-	if (char1 == ' ' && meta)	/* <space> <char> --> meta-char */
+	if (char1 == ' ' && meta_char)	/* <space> <char> --> meta-char */
 	    return (char2 | 0x80);
 	return char2;
     }
@@ -2171,16 +2171,16 @@
  * Allow for both char1-char2 and char2-char1
  */
     int
-getdigraph(char1, char2, meta)
+getdigraph(char1, char2, meta_char)
     int	char1;
     int	char2;
-    int	meta;
+    int	meta_char;
 {
     int	    retval;
 
-    if (((retval = getexactdigraph(char1, char2, meta)) == char2)
+    if (((retval = getexactdigraph(char1, char2, meta_char)) == char2)
 	    && (char1 != char2)
-	    && ((retval = getexactdigraph(char2, char1, meta)) == char1))
+	    && ((retval = getexactdigraph(char2, char1, meta_char)) == char1))
 	return char2;
     return retval;
 }
diff --git a/src/edit.c b/src/edit.c
index daab0fe..4289ff5 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -4003,24 +4003,24 @@
 ins_compl_add_dict(dict)
     dict_T	*dict;
 {
-    dictitem_T	*refresh;
-    dictitem_T	*words;
+    dictitem_T	*di_refresh;
+    dictitem_T	*di_words;
 
     /* Check for optional "refresh" item. */
     compl_opt_refresh_always = FALSE;
-    refresh = dict_find(dict, (char_u *)"refresh", 7);
-    if (refresh != NULL && refresh->di_tv.v_type == VAR_STRING)
+    di_refresh = dict_find(dict, (char_u *)"refresh", 7);
+    if (di_refresh != NULL && di_refresh->di_tv.v_type == VAR_STRING)
     {
-	char_u	*v = refresh->di_tv.vval.v_string;
+	char_u	*v = di_refresh->di_tv.vval.v_string;
 
 	if (v != NULL && STRCMP(v, (char_u *)"always") == 0)
 	    compl_opt_refresh_always = TRUE;
     }
 
     /* Add completions from a "words" list. */
-    words = dict_find(dict, (char_u *)"words", 5);
-    if (words != NULL && words->di_tv.v_type == VAR_LIST)
-	ins_compl_add_list(words->di_tv.vval.v_list);
+    di_words = dict_find(dict, (char_u *)"words", 5);
+    if (di_words != NULL && di_words->di_tv.v_type == VAR_LIST)
+	ins_compl_add_list(di_words->di_tv.vval.v_list);
 }
 
 /*
diff --git a/src/eval.c b/src/eval.c
index 402d09d..16e740f 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -6573,15 +6573,15 @@
 
 /*
  * Join list "l" into a string in "*gap", using separator "sep".
- * When "echo" is TRUE use String as echoed, otherwise as inside a List.
+ * When "echo_style" is TRUE use String as echoed, otherwise as inside a List.
  * Return FAIL or OK.
  */
     static int
-list_join(gap, l, sep, echo, copyID)
+list_join(gap, l, sep, echo_style, copyID)
     garray_T	*gap;
     list_T	*l;
     char_u	*sep;
-    int		echo;
+    int		echo_style;
     int		copyID;
 {
     int		first = TRUE;
@@ -6597,7 +6597,7 @@
 	else
 	    ga_concat(gap, sep);
 
-	if (echo)
+	if (echo_style)
 	    s = echo_string(&item->li_tv, &tofree, numbuf, copyID);
 	else
 	    s = tv2string(&item->li_tv, &tofree, numbuf, copyID);
@@ -17893,7 +17893,7 @@
     typval_T	*argvars;
     typval_T	*rettv;
 {
-    char_u	*instr;
+    char_u	*in_str;
     char_u	*fromstr;
     char_u	*tostr;
     char_u	*p;
@@ -17910,7 +17910,7 @@
     char_u	buf2[NUMBUFLEN];
     garray_T	ga;
 
-    instr = get_tv_string(&argvars[0]);
+    in_str = get_tv_string(&argvars[0]);
     fromstr = get_tv_string_buf_chk(&argvars[1], buf);
     tostr = get_tv_string_buf_chk(&argvars[2], buf2);
 
@@ -17936,19 +17936,19 @@
 	}
 
     /* fromstr and tostr have to contain the same number of chars */
-    while (*instr != NUL)
+    while (*in_str != NUL)
     {
 #ifdef FEAT_MBYTE
 	if (has_mbyte)
 	{
-	    inlen = (*mb_ptr2len)(instr);
-	    cpstr = instr;
+	    inlen = (*mb_ptr2len)(in_str);
+	    cpstr = in_str;
 	    cplen = inlen;
 	    idx = 0;
 	    for (p = fromstr; *p != NUL; p += fromlen)
 	    {
 		fromlen = (*mb_ptr2len)(p);
-		if (fromlen == inlen && STRNCMP(instr, p, inlen) == 0)
+		if (fromlen == inlen && STRNCMP(in_str, p, inlen) == 0)
 		{
 		    for (p = tostr; *p != NUL; p += tolen)
 		    {
@@ -17967,11 +17967,11 @@
 		++idx;
 	    }
 
-	    if (first && cpstr == instr)
+	    if (first && cpstr == in_str)
 	    {
 		/* Check that fromstr and tostr have the same number of
 		 * (multi-byte) characters.  Done only once when a character
-		 * of instr doesn't appear in fromstr. */
+		 * of in_str doesn't appear in fromstr. */
 		first = FALSE;
 		for (p = tostr; *p != NUL; p += tolen)
 		{
@@ -17986,18 +17986,18 @@
 	    mch_memmove((char *)ga.ga_data + ga.ga_len, cpstr, (size_t)cplen);
 	    ga.ga_len += cplen;
 
-	    instr += inlen;
+	    in_str += inlen;
 	}
 	else
 #endif
 	{
 	    /* When not using multi-byte chars we can do it faster. */
-	    p = vim_strchr(fromstr, *instr);
+	    p = vim_strchr(fromstr, *in_str);
 	    if (p != NULL)
 		ga_append(&ga, tostr[p - fromstr]);
 	    else
-		ga_append(&ga, *instr);
-	    ++instr;
+		ga_append(&ga, *in_str);
+	    ++in_str;
 	}
     }
 
diff --git a/src/fold.c b/src/fold.c
index 3b7a959..4d294f1 100644
--- a/src/fold.c
+++ b/src/fold.c
@@ -1033,10 +1033,10 @@
  * Init the fold info in a new window.
  */
     void
-foldInitWin(newwin)
-    win_T	*newwin;
+foldInitWin(new_win)
+    win_T	*new_win;
 {
-    ga_init2(&newwin->w_folds, (int)sizeof(fold_T), 10);
+    ga_init2(&new_win->w_folds, (int)sizeof(fold_T), 10);
 }
 
 /* find_wl_entry() {{{2 */
diff --git a/src/getchar.c b/src/getchar.c
index c4457c4..3d6b0b2 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -418,12 +418,12 @@
 
 /*
  * Remove the contents of the stuff buffer and the mapped characters in the
- * typeahead buffer (used in case of an error).  If 'typeahead' is true,
+ * typeahead buffer (used in case of an error).  If "flush_typeahead" is true,
  * flush all typeahead characters (used when interrupted by a CTRL-C).
  */
     void
-flush_buffers(typeahead)
-    int typeahead;
+flush_buffers(flush_typeahead)
+    int flush_typeahead;
 {
     init_typebuf();
 
@@ -431,7 +431,7 @@
     while (read_stuff(TRUE) != NUL)
 	;
 
-    if (typeahead)	    /* remove all typeahead */
+    if (flush_typeahead)	    /* remove all typeahead */
     {
 	/*
 	 * We have to get all characters, because we may delete the first part
diff --git a/src/message.c b/src/message.c
index 6cd3fa2..03a7ea5 100644
--- a/src/message.c
+++ b/src/message.c
@@ -2487,7 +2487,7 @@
 #ifdef FEAT_CON_DIALOG
     int		retval = FALSE;
 #endif
-    int		scroll;
+    int		toscroll;
     msgchunk_T	*mp_last = NULL;
     msgchunk_T	*mp;
     int		i;
@@ -2538,49 +2538,49 @@
 	}
 #endif
 
-	scroll = 0;
+	toscroll = 0;
 	switch (c)
 	{
 	case BS:		/* scroll one line back */
 	case K_BS:
 	case 'k':
 	case K_UP:
-	    scroll = -1;
+	    toscroll = -1;
 	    break;
 
 	case CAR:		/* one extra line */
 	case NL:
 	case 'j':
 	case K_DOWN:
-	    scroll = 1;
+	    toscroll = 1;
 	    break;
 
 	case 'u':		/* Up half a page */
-	    scroll = -(Rows / 2);
+	    toscroll = -(Rows / 2);
 	    break;
 
 	case 'd':		/* Down half a page */
-	    scroll = Rows / 2;
+	    toscroll = Rows / 2;
 	    break;
 
 	case 'b':		/* one page back */
 	case K_PAGEUP:
-	    scroll = -(Rows - 1);
+	    toscroll = -(Rows - 1);
 	    break;
 
 	case ' ':		/* one extra page */
 	case 'f':
 	case K_PAGEDOWN:
 	case K_LEFTMOUSE:
-	    scroll = Rows - 1;
+	    toscroll = Rows - 1;
 	    break;
 
 	case 'g':		/* all the way back to the start */
-	    scroll = -999999;
+	    toscroll = -999999;
 	    break;
 
 	case 'G':		/* all the way to the end */
-	    scroll = 999999;
+	    toscroll = 999999;
 	    lines_left = 999999;
 	    break;
 
@@ -2633,9 +2633,9 @@
 	    continue;
 	}
 
-	if (scroll != 0)
+	if (toscroll != 0)
 	{
-	    if (scroll < 0)
+	    if (toscroll < 0)
 	    {
 		/* go to start of last line */
 		if (mp_last == NULL)
@@ -2653,7 +2653,7 @@
 		if (mp != NULL && mp->sb_prev != NULL)
 		{
 		    /* Find line to be displayed at top. */
-		    for (i = 0; i > scroll; --i)
+		    for (i = 0; i > toscroll; --i)
 		    {
 			if (mp == NULL || mp->sb_prev == NULL)
 			    break;
@@ -2664,7 +2664,7 @@
 			    mp_last = msg_sb_start(mp_last->sb_prev);
 		    }
 
-		    if (scroll == -1 && screen_ins_lines(0, 0, 1,
+		    if (toscroll == -1 && screen_ins_lines(0, 0, 1,
 						       (int)Rows, NULL) == OK)
 		    {
 			/* display line at top */
@@ -2680,13 +2680,13 @@
 			    ++msg_scrolled;
 			}
 		    }
-		    scroll = 0;
+		    toscroll = 0;
 		}
 	    }
 	    else
 	    {
 		/* First display any text that we scrolled back. */
-		while (scroll > 0 && mp_last != NULL)
+		while (toscroll > 0 && mp_last != NULL)
 		{
 		    /* scroll up, display line at bottom */
 		    msg_scroll_up();
@@ -2694,11 +2694,11 @@
 		    screen_fill((int)Rows - 2, (int)Rows - 1, 0,
 						   (int)Columns, ' ', ' ', 0);
 		    mp_last = disp_sb_line((int)Rows - 2, mp_last);
-		    --scroll;
+		    --toscroll;
 		}
 	    }
 
-	    if (scroll <= 0)
+	    if (toscroll <= 0)
 	    {
 		/* displayed the requested text, more prompt again */
 		screen_fill((int)Rows - 1, (int)Rows, 0,
@@ -2708,7 +2708,7 @@
 	    }
 
 	    /* display more text, return to caller */
-	    lines_left = scroll;
+	    lines_left = toscroll;
 	}
 
 	break;
diff --git a/src/misc2.c b/src/misc2.c
index 96c3a36..22d1fb4 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -1559,7 +1559,7 @@
 	    if (enc_utf8)
 	    {
 		int	c, uc;
-		int	nl;
+		int	newl;
 		char_u	*s;
 
 		c = utf_ptr2char(p);
@@ -1568,21 +1568,21 @@
 		/* Reallocate string when byte count changes.  This is rare,
 		 * thus it's OK to do another malloc()/free(). */
 		l = utf_ptr2len(p);
-		nl = utf_char2len(uc);
-		if (nl != l)
+		newl = utf_char2len(uc);
+		if (newl != l)
 		{
-		    s = alloc((unsigned)STRLEN(res) + 1 + nl - l);
+		    s = alloc((unsigned)STRLEN(res) + 1 + newl - l);
 		    if (s == NULL)
 			break;
 		    mch_memmove(s, res, p - res);
-		    STRCPY(s + (p - res) + nl, p + l);
+		    STRCPY(s + (p - res) + newl, p + l);
 		    p = s + (p - res);
 		    vim_free(res);
 		    res = s;
 		}
 
 		utf_char2bytes(uc, p);
-		p += nl;
+		p += newl;
 	    }
 	    else if (has_mbyte && (l = (*mb_ptr2len)(p)) > 1)
 		p += l;		/* skip multi-byte character */
diff --git a/src/move.c b/src/move.c
index 79df928..f922da8 100644
--- a/src/move.c
+++ b/src/move.c
@@ -926,8 +926,8 @@
  * Also updates curwin->w_leftcol.
  */
     void
-curs_columns(scroll)
-    int		scroll;		/* when TRUE, may scroll horizontally */
+curs_columns(may_scroll)
+    int		may_scroll;	/* when TRUE, may scroll horizontally */
 {
     int		diff;
     int		extra;		/* offset for first screen line */
@@ -1014,7 +1014,7 @@
     /* No line wrapping: compute curwin->w_leftcol if scrolling is on and line
      * is not folded.
      * If scrolling is off, curwin->w_leftcol is assumed to be 0 */
-    else if (scroll
+    else if (may_scroll
 #ifdef FEAT_FOLDING
 	    && !curwin->w_cline_folded
 #endif
diff --git a/src/netbeans.c b/src/netbeans.c
index 59348f0..267daff 100644
--- a/src/netbeans.c
+++ b/src/netbeans.c
@@ -1395,7 +1395,7 @@
     int		cmdno,
     char_u	*args)	    /* points to space before arguments or NUL */
 {
-    int		doupdate = 0;
+    int		do_update = 0;
     long	off = 0;
     nbbuf_T	*buf = nb_get_buf(bufno);
     static int	skip = 0;
@@ -1600,7 +1600,7 @@
 							last.lnum, last.col));
 		del_from_lnum = first.lnum;
 		del_to_lnum = last.lnum;
-		doupdate = 1;
+		do_update = 1;
 
 		/* Get the position of the first byte after the deleted
 		 * section.  "next" is NULL when deleting to the end of the
@@ -1777,7 +1777,7 @@
 		lnum = lnum_start;
 
 		/* Loop over the "\n" separated lines of the argument. */
-		doupdate = 1;
+		do_update = 1;
 		while (*args != NUL)
 		{
 		    nl = vim_strchr(args, '\n');
@@ -1992,7 +1992,7 @@
 		EMSG("E640: invalid buffer identifier in initDone");
 		return FAIL;
 	    }
-	    doupdate = 1;
+	    do_update = 1;
 	    buf->initDone = TRUE;
 	    nb_set_curbuf(buf->bufp);
 #if defined(FEAT_AUTOCMD)
@@ -2081,7 +2081,7 @@
 					     ECMD_HIDE + ECMD_OLDBUF, curwin);
 	    buf->bufp = curbuf;
 	    buf->initDone = TRUE;
-	    doupdate = 1;
+	    do_update = 1;
 #if defined(FEAT_TITLE)
 	    maketitle();
 #endif
@@ -2109,7 +2109,7 @@
 		exarg.forceit = FALSE;
 		dosetvisible = TRUE;
 		goto_buffer(&exarg, DOBUF_FIRST, FORWARD, buf->bufp->b_fnum);
-		doupdate = 1;
+		do_update = 1;
 		dosetvisible = FALSE;
 
 #ifdef FEAT_GUI
@@ -2309,7 +2309,7 @@
 						     buf->bufp->b_fnum, TRUE);
 	    buf->bufp = NULL;
 	    buf->initDone = FALSE;
-	    doupdate = 1;
+	    do_update = 1;
 /* =====================================================================*/
 	}
 	else if (streq((char *)cmd, "setStyle")) /* obsolete... */
@@ -2400,7 +2400,7 @@
 		return FAIL;
 	    }
 
-	    doupdate = 1;
+	    do_update = 1;
 
 	    cp = (char *)args;
 	    serNum = strtol(cp, &cp, 10);
@@ -2448,7 +2448,7 @@
 		nbdebug(("    invalid buffer identifier in removeAnno\n"));
 		return FAIL;
 	    }
-	    doupdate = 1;
+	    do_update = 1;
 	    cp = (char *)args;
 	    serNum = strtol(cp, &cp, 10);
 	    args = (char_u *)cp;
@@ -2493,7 +2493,7 @@
 	    len = strtol(cp, NULL, 10);
 	    args = (char_u *)cp;
 	    pos = off2pos(buf->bufp, off);
-	    doupdate = 1;
+	    do_update = 1;
 	    if (!pos)
 		nbdebug(("    no such start pos in %s, %ld\n", cmd, off));
 	    else
@@ -2555,7 +2555,7 @@
 	    inAtomic = 0;
 	    if (needupdate)
 	    {
-		doupdate = 1;
+		do_update = 1;
 		needupdate = 0;
 	    }
 /* =====================================================================*/
@@ -2636,18 +2636,18 @@
 	 * Unrecognized command is ignored.
 	 */
     }
-    if (inAtomic && doupdate)
+    if (inAtomic && do_update)
     {
 	needupdate = 1;
-	doupdate = 0;
+	do_update = 0;
     }
 
     /*
      * Is this needed? I moved the netbeans_Xt_connect() later during startup
      * and it may no longer be necessary. If its not needed then needupdate
-     * and doupdate can also be removed.
+     * and do_update can also be removed.
      */
-    if (buf != NULL && buf->initDone && doupdate)
+    if (buf != NULL && buf->initDone && do_update)
     {
 	update_screen(NOT_VALID);
 	setcursor();
diff --git a/src/option.c b/src/option.c
index f6ed2d3..60956d7 100644
--- a/src/option.c
+++ b/src/option.c
@@ -8584,8 +8584,8 @@
     long_u	flags;
 {
     /* Careful: P_RCLR and P_RALL are a combination of other P_ flags */
-    int		clear = (flags & P_RCLR) == P_RCLR;
-    int		all = ((flags & P_RALL) == P_RALL || clear);
+    int		doclear = (flags & P_RCLR) == P_RCLR;
+    int		all = ((flags & P_RALL) == P_RALL || doclear);
 
 #ifdef FEAT_WINDOWS
     if ((flags & P_RSTAT) || all)	/* mark all status lines dirty */
@@ -8596,7 +8596,7 @@
 	changed_window_setting();
     if (flags & P_RBUF)
 	redraw_curbuf_later(NOT_VALID);
-    if (clear)
+    if (doclear)
 	redraw_all_later(CLEAR);
     else if (all)
 	redraw_all_later(NOT_VALID);
diff --git a/src/os_unix.c b/src/os_unix.c
index cdf5abe..30593ef 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -3884,7 +3884,6 @@
     char_u	*p_shcf_copy = NULL;
     int		i;
     char_u	*p;
-    char_u	*s;
     int		inquote;
     int		pty_master_fd = -1;	    /* for pty's */
 # ifdef FEAT_GUI
@@ -3963,6 +3962,8 @@
     }
     if (cmd != NULL)
     {
+	char_u	*s;
+
 	if (extra_shell_arg != NULL)
 	    argv[argc++] = (char *)extra_shell_arg;
 
@@ -4325,7 +4326,6 @@
 			linenr_T    lnum = curbuf->b_op_start.lnum;
 			int	    written = 0;
 			char_u	    *lp = ml_get(lnum);
-			char_u	    *s;
 			size_t	    l;
 
 			close(fromshell_fd);
@@ -4339,7 +4339,8 @@
 				len = write(toshell_fd, "", (size_t)1);
 			    else
 			    {
-				s = vim_strchr(lp + written, NL);
+				char_u	*s = vim_strchr(lp + written, NL);
+
 				len = write(toshell_fd, (char *)lp + written,
 					   s == NULL ? l
 					      : (size_t)(s - (lp + written)));
diff --git a/src/screen.c b/src/screen.c
index ad2d345..ffbd1c3 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -7849,15 +7849,15 @@
 
 /*
  * screen_valid -  allocate screen buffers if size changed
- *   If "clear" is TRUE: clear screen if it has been resized.
+ *   If "doclear" is TRUE: clear screen if it has been resized.
  *	Returns TRUE if there is a valid screen to write to.
  *	Returns FALSE when starting up and screen not initialized yet.
  */
     int
-screen_valid(clear)
-    int	    clear;
+screen_valid(doclear)
+    int	    doclear;
 {
-    screenalloc(clear);	    /* allocate screen buffers if size changed */
+    screenalloc(doclear);	   /* allocate screen buffers if size changed */
     return (ScreenLines != NULL);
 }
 
@@ -7872,8 +7872,8 @@
  * final size of the shell is needed.
  */
     void
-screenalloc(clear)
-    int	    clear;
+screenalloc(doclear)
+    int	    doclear;
 {
     int		    new_row, old_row;
 #ifdef FEAT_GUI
@@ -8069,7 +8069,7 @@
 	     * (used when resizing the window at the "--more--" prompt or when
 	     * executing an external command, for the GUI).
 	     */
-	    if (!clear)
+	    if (!doclear)
 	    {
 		(void)vim_memset(new_ScreenLines + new_row * Columns,
 				      ' ', (size_t)Columns * sizeof(schar_T));
@@ -8159,7 +8159,7 @@
     screen_Columns = Columns;
 
     must_redraw = CLEAR;	/* need to clear the screen later */
-    if (clear)
+    if (doclear)
 	screenclear2();
 
 #ifdef FEAT_GUI
diff --git a/src/search.c b/src/search.c
index 5a6a940..c9d4b5e 100644
--- a/src/search.c
+++ b/src/search.c
@@ -2402,24 +2402,24 @@
     {
 	if (vim_strchr(p, ';') != NULL) /* there may be comments */
 	{
-	    int instr = FALSE;	/* inside of string */
+	    int in_str = FALSE;	/* inside of string */
 
 	    p = line;		/* scan from start */
 	    while ((p = vim_strpbrk(p, (char_u *)"\";")) != NULL)
 	    {
 		if (*p == '"')
 		{
-		    if (instr)
+		    if (in_str)
 		    {
 			if (*(p - 1) != '\\') /* skip escaped quote */
-			    instr = FALSE;
+			    in_str = FALSE;
 		    }
 		    else if (p == line || ((p - line) >= 2
 				      /* skip #\" form */
 				      && *(p - 1) != '\\' && *(p - 2) != '#'))
-			instr = TRUE;
+			in_str = TRUE;
 		}
-		else if (!instr && ((p - line) < 2
+		else if (!in_str && ((p - line) < 2
 				    || (*(p - 1) != '\\' && *(p - 2) != '#')))
 		    break;	/* found! */
 		++p;
diff --git a/src/spell.c b/src/spell.c
index f7ec0c7..f3d64e7 100644
--- a/src/spell.c
+++ b/src/spell.c
@@ -5049,7 +5049,7 @@
 static int offset2bytes __ARGS((int nr, char_u *buf));
 static int bytes2offset __ARGS((char_u **pp));
 static void sug_write __ARGS((spellinfo_T *spin, char_u *fname));
-static void mkspell __ARGS((int fcount, char_u **fnames, int ascii, int overwrite, int added_word));
+static void mkspell __ARGS((int fcount, char_u **fnames, int ascii, int over_write, int added_word));
 static void spell_message __ARGS((spellinfo_T *spin, char_u *str));
 static void init_spellfile __ARGS((void));
 
@@ -9085,11 +9085,11 @@
  * and ".spl" is appended to make the output file name.
  */
     static void
-mkspell(fcount, fnames, ascii, overwrite, added_word)
+mkspell(fcount, fnames, ascii, over_write, added_word)
     int		fcount;
     char_u	**fnames;
     int		ascii;		    /* -ascii argument given */
-    int		overwrite;	    /* overwrite existing output file */
+    int		over_write;	    /* overwrite existing output file */
     int		added_word;	    /* invoked through "zg" */
 {
     char_u	*fname = NULL;
@@ -9173,7 +9173,7 @@
     {
 	/* Check for overwriting before doing things that may take a lot of
 	 * time. */
-	if (!overwrite && mch_stat((char *)wfname, &st) >= 0)
+	if (!over_write && mch_stat((char *)wfname, &st) >= 0)
 	{
 	    EMSG(_(e_exists));
 	    goto theend;
diff --git a/src/syntax.c b/src/syntax.c
index f3cb71e..d63c260 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -4006,17 +4006,17 @@
 }
 
     static void
-syn_list_flags(nl, flags, attr)
-    struct name_list	*nl;
+syn_list_flags(nlist, flags, attr)
+    struct name_list	*nlist;
     int			flags;
     int			attr;
 {
     int		i;
 
-    for (i = 0; nl[i].flag != 0; ++i)
-	if (flags & nl[i].flag)
+    for (i = 0; nlist[i].flag != 0; ++i)
+	if (flags & nlist[i].flag)
 	{
-	    msg_puts_attr((char_u *)nl[i].name, attr);
+	    msg_puts_attr((char_u *)nlist[i].name, attr);
 	    msg_putchar(' ');
 	}
 }
diff --git a/src/tag.c b/src/tag.c
index 41c7c58..08abd41 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -1353,7 +1353,6 @@
     int		match_count = 0;		/* number of matches found */
     char_u	**matches;
     int		mtt;
-    int		len;
     int		help_save;
 #ifdef FEAT_MULTI_LANG
     int		help_pri = 0;
@@ -2235,6 +2234,8 @@
 		 */
 		if (ga_grow(&ga_match[mtt], 1) == OK)
 		{
+		    int len;
+
 		    if (help_only)
 		    {
 #ifdef FEAT_MULTI_LANG
diff --git a/src/version.c b/src/version.c
index f5e79e5..fbafa05 100644
--- a/src/version.c
+++ b/src/version.c
@@ -715,6 +715,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    400,
+/**/
     399,
 /**/
     398,
diff --git a/src/window.c b/src/window.c
index 80c69a1..9c43374 100644
--- a/src/window.c
+++ b/src/window.c
@@ -683,19 +683,19 @@
 }
 
 /*
- * When "newwin" is NULL: split the current window in two.
- * When "newwin" is not NULL: insert this window at the far
+ * When "new_wp" is NULL: split the current window in two.
+ * When "new_wp" is not NULL: insert this window at the far
  * top/left/right/bottom.
  * return FAIL for failure, OK otherwise
  */
     int
-win_split_ins(size, flags, newwin, dir)
+win_split_ins(size, flags, new_wp, dir)
     int		size;
     int		flags;
-    win_T	*newwin;
+    win_T	*new_wp;
     int		dir;
 {
-    win_T	*wp = newwin;
+    win_T	*wp = new_wp;
     win_T	*oldwin;
     int		new_size = size;
     int		i;
@@ -718,7 +718,7 @@
     /* add a status line when p_ls == 1 and splitting the first window */
     if (lastwin == firstwin && p_ls == 1 && oldwin->w_status_height == 0)
     {
-	if (oldwin->w_height <= p_wmh && newwin == NULL)
+	if (oldwin->w_height <= p_wmh && new_wp == NULL)
 	{
 	    EMSG(_(e_noroom));
 	    return FAIL;
@@ -751,7 +751,7 @@
 	}
 	else
 	    available = oldwin->w_width;
-	if (available < needed && newwin == NULL)
+	if (available < needed && new_wp == NULL)
 	{
 	    EMSG(_(e_noroom));
 	    return FAIL;
@@ -815,7 +815,7 @@
 	    available = oldwin->w_height;
 	    needed += p_wmh;
 	}
-	if (available < needed && newwin == NULL)
+	if (available < needed && new_wp == NULL)
 	{
 	    EMSG(_(e_noroom));
 	    return FAIL;
@@ -888,20 +888,20 @@
 			p_sb))))
     {
 	/* new window below/right of current one */
-	if (newwin == NULL)
+	if (new_wp == NULL)
 	    wp = win_alloc(oldwin, FALSE);
 	else
 	    win_append(oldwin, wp);
     }
     else
     {
-	if (newwin == NULL)
+	if (new_wp == NULL)
 	    wp = win_alloc(oldwin->w_prev, FALSE);
 	else
 	    win_append(oldwin->w_prev, wp);
     }
 
-    if (newwin == NULL)
+    if (new_wp == NULL)
     {
 	if (wp == NULL)
 	    return FAIL;
@@ -972,10 +972,10 @@
 		frp->fr_parent = curfrp;
     }
 
-    if (newwin == NULL)
+    if (new_wp == NULL)
 	frp = wp->w_frame;
     else
-	frp = newwin->w_frame;
+	frp = new_wp->w_frame;
     frp->fr_parent = curfrp->fr_parent;
 
     /* Insert the new frame at the right place in the frame list. */
@@ -4284,19 +4284,19 @@
     win_T	*after UNUSED;
     int		hidden UNUSED;
 {
-    win_T	*newwin;
+    win_T	*new_wp;
 
     /*
      * allocate window structure and linesizes arrays
      */
-    newwin = (win_T *)alloc_clear((unsigned)sizeof(win_T));
-    if (newwin != NULL && win_alloc_lines(newwin) == FAIL)
+    new_wp = (win_T *)alloc_clear((unsigned)sizeof(win_T));
+    if (new_wp != NULL && win_alloc_lines(new_wp) == FAIL)
     {
-	vim_free(newwin);
-	newwin = NULL;
+	vim_free(new_wp);
+	new_wp = NULL;
     }
 
-    if (newwin != NULL)
+    if (new_wp != NULL)
     {
 #ifdef FEAT_AUTOCMD
 	/* Don't execute autocommands while the window is not properly
@@ -4309,53 +4309,53 @@
 	 */
 #ifdef FEAT_WINDOWS
 	if (!hidden)
-	    win_append(after, newwin);
+	    win_append(after, new_wp);
 #endif
 #ifdef FEAT_VERTSPLIT
-	newwin->w_wincol = 0;
-	newwin->w_width = Columns;
+	new_wp->w_wincol = 0;
+	new_wp->w_width = Columns;
 #endif
 
 	/* position the display and the cursor at the top of the file. */
-	newwin->w_topline = 1;
+	new_wp->w_topline = 1;
 #ifdef FEAT_DIFF
-	newwin->w_topfill = 0;
+	new_wp->w_topfill = 0;
 #endif
-	newwin->w_botline = 2;
-	newwin->w_cursor.lnum = 1;
+	new_wp->w_botline = 2;
+	new_wp->w_cursor.lnum = 1;
 #ifdef FEAT_SCROLLBIND
-	newwin->w_scbind_pos = 1;
+	new_wp->w_scbind_pos = 1;
 #endif
 
 	/* We won't calculate w_fraction until resizing the window */
-	newwin->w_fraction = 0;
-	newwin->w_prev_fraction_row = -1;
+	new_wp->w_fraction = 0;
+	new_wp->w_prev_fraction_row = -1;
 
 #ifdef FEAT_GUI
 	if (gui.in_use)
 	{
-	    gui_create_scrollbar(&newwin->w_scrollbars[SBAR_LEFT],
-		    SBAR_LEFT, newwin);
-	    gui_create_scrollbar(&newwin->w_scrollbars[SBAR_RIGHT],
-		    SBAR_RIGHT, newwin);
+	    gui_create_scrollbar(&new_wp->w_scrollbars[SBAR_LEFT],
+		    SBAR_LEFT, new_wp);
+	    gui_create_scrollbar(&new_wp->w_scrollbars[SBAR_RIGHT],
+		    SBAR_RIGHT, new_wp);
 	}
 #endif
 #ifdef FEAT_EVAL
 	/* init w: variables */
-	init_var_dict(&newwin->w_vars, &newwin->w_winvar);
+	init_var_dict(&new_wp->w_vars, &new_wp->w_winvar);
 #endif
 #ifdef FEAT_FOLDING
-	foldInitWin(newwin);
+	foldInitWin(new_wp);
 #endif
 #ifdef FEAT_AUTOCMD
 	unblock_autocmds();
 #endif
 #ifdef FEAT_SEARCH_EXTRA
-	newwin->w_match_head = NULL;
-	newwin->w_next_match_id = 4;
+	new_wp->w_match_head = NULL;
+	new_wp->w_next_match_id = 4;
 #endif
     }
-    return newwin;
+    return new_wp;
 }
 
 #if defined(FEAT_WINDOWS) || defined(PROTO)