diff --git a/contrib/minizip/iowin32.c b/contrib/minizip/iowin32.c
index 08536e9..49f5ba1 100644
--- a/contrib/minizip/iowin32.c
+++ b/contrib/minizip/iowin32.c
@@ -89,7 +89,7 @@
 }
 
 voidpf ZCALLBACK win32_open64_file_func(voidpf opaque, const void* filename, int mode) {
-    const char* mode_fopen = NULL;
+    (void)opaque;
     DWORD dwDesiredAccess,dwCreationDisposition,dwShareMode,dwFlagsAndAttributes ;
     HANDLE hFile = NULL;
 
@@ -117,7 +117,7 @@
 
 
 voidpf ZCALLBACK win32_open64_file_funcA(voidpf opaque, const void* filename, int mode) {
-    const char* mode_fopen = NULL;
+    (void)opaque;
     DWORD dwDesiredAccess,dwCreationDisposition,dwShareMode,dwFlagsAndAttributes ;
     HANDLE hFile = NULL;
 
@@ -140,7 +140,7 @@
 
 
 voidpf ZCALLBACK win32_open64_file_funcW(voidpf opaque, const void* filename, int mode) {
-    const char* mode_fopen = NULL;
+    (void)opaque;
     DWORD dwDesiredAccess,dwCreationDisposition,dwShareMode,dwFlagsAndAttributes ;
     HANDLE hFile = NULL;
 
@@ -159,7 +159,7 @@
 
 
 voidpf ZCALLBACK win32_open_file_func(voidpf opaque, const char* filename, int mode) {
-    const char* mode_fopen = NULL;
+    (void)opaque;
     DWORD dwDesiredAccess,dwCreationDisposition,dwShareMode,dwFlagsAndAttributes ;
     HANDLE hFile = NULL;
 
@@ -187,6 +187,7 @@
 
 
 uLong ZCALLBACK win32_read_file_func(voidpf opaque, voidpf stream, void* buf,uLong size) {
+    (void)opaque;
     uLong ret=0;
     HANDLE hFile = NULL;
     if (stream!=NULL)
@@ -208,6 +209,7 @@
 
 
 uLong ZCALLBACK win32_write_file_func(voidpf opaque, voidpf stream, const void* buf, uLong size) {
+    (void)opaque;
     uLong ret=0;
     HANDLE hFile = NULL;
     if (stream!=NULL)
@@ -247,6 +249,7 @@
 }
 
 long ZCALLBACK win32_tell_file_func(voidpf opaque, voidpf stream) {
+    (void)opaque;
     long ret=-1;
     HANDLE hFile = NULL;
     if (stream!=NULL)
@@ -269,6 +272,7 @@
 }
 
 ZPOS64_T ZCALLBACK win32_tell64_file_func(voidpf opaque, voidpf stream) {
+    (void)opaque;
     ZPOS64_T ret= (ZPOS64_T)-1;
     HANDLE hFile = NULL;
     if (stream!=NULL)
@@ -293,6 +297,7 @@
 
 
 long ZCALLBACK win32_seek_file_func(voidpf opaque, voidpf stream, uLong offset, int origin) {
+    (void)opaque;
     DWORD dwMoveMethod=0xFFFFFFFF;
     HANDLE hFile = NULL;
 
@@ -330,6 +335,7 @@
 }
 
 long ZCALLBACK win32_seek64_file_func(voidpf opaque, voidpf stream, ZPOS64_T offset, int origin) {
+    (void)opaque;
     DWORD dwMoveMethod=0xFFFFFFFF;
     HANDLE hFile = NULL;
     long ret=-1;
@@ -368,6 +374,7 @@
 }
 
 int ZCALLBACK win32_close_file_func(voidpf opaque, voidpf stream) {
+    (void)opaque;
     int ret=-1;
 
     if (stream!=NULL)
@@ -385,6 +392,7 @@
 }
 
 int ZCALLBACK win32_error_file_func(voidpf opaque, voidpf stream) {
+    (void)opaque;
     int ret=-1;
     if (stream!=NULL)
     {
diff --git a/contrib/minizip/miniunz.c b/contrib/minizip/miniunz.c
index 8e19534..616c303 100644
--- a/contrib/minizip/miniunz.c
+++ b/contrib/minizip/miniunz.c
@@ -39,6 +39,9 @@
 #endif
 
 
+#ifndef _CRT_SECURE_NO_WARNINGS
+#  define _CRT_SECURE_NO_WARNINGS
+#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -83,6 +86,7 @@
     tmu_date : the SAME new date at the tm_unz format */
 static void change_file_date(const char *filename, uLong dosdate, tm_unz tmu_date) {
 #ifdef _WIN32
+  (void)tmu_date;
   HANDLE hFile;
   FILETIME ftm,ftLocal,ftCreate,ftLastAcc,ftLastWrite;
 
diff --git a/contrib/minizip/minizip.c b/contrib/minizip/minizip.c
index 4d93d22..66e88d0 100644
--- a/contrib/minizip/minizip.c
+++ b/contrib/minizip/minizip.c
@@ -41,6 +41,9 @@
 
 
 
+#ifndef _CRT_SECURE_NO_WARNINGS
+#  define _CRT_SECURE_NO_WARNINGS
+#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -74,6 +77,7 @@
 /* f: name of file to get info on, tmzip: return value: access,
    modification and creation times, dt: dostime */
 static int filetime(const char *f, tm_zip *tmzip, uLong *dt) {
+  (void)tmzip;
   int ret = 0;
   {
       FILETIME ftLocal;
@@ -190,7 +194,7 @@
         do
         {
             err = ZIP_OK;
-            size_read = fread(buf,1,size_buf,fin);
+            size_read = (unsigned long)fread(buf,1,size_buf,fin);
             if (size_read < size_buf)
                 if (feof(fin)==0)
             {
@@ -242,7 +246,7 @@
     char filename_try[MAXFILENAME+16];
     int zipok;
     int err=0;
-    size_t size_buf=0;
+    unsigned long size_buf=0;
     void* buf=NULL;
     const char* password=NULL;
 
@@ -304,7 +308,7 @@
     }
     else
     {
-        int i,len;
+        int len;
         int dot_found=0;
 
         zipok = 1 ;
diff --git a/contrib/minizip/mztools.c b/contrib/minizip/mztools.c
index c8d2375..f86c1e7 100644
--- a/contrib/minizip/mztools.c
+++ b/contrib/minizip/mztools.c
@@ -5,6 +5,9 @@
 */
 
 /* Code */
+#ifndef _CRT_SECURE_NO_WARNINGS
+#  define _CRT_SECURE_NO_WARNINGS
+#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -140,28 +143,28 @@
 
         /* Central directory entry */
         {
-          char header[46];
+          char central[46];
           char* comment = "";
           int comsize = (int) strlen(comment);
-          WRITE_32(header, 0x02014b50);
-          WRITE_16(header + 4, version);
-          WRITE_16(header + 6, version);
-          WRITE_16(header + 8, gpflag);
-          WRITE_16(header + 10, method);
-          WRITE_16(header + 12, filetime);
-          WRITE_16(header + 14, filedate);
-          WRITE_32(header + 16, crc);
-          WRITE_32(header + 20, cpsize);
-          WRITE_32(header + 24, uncpsize);
-          WRITE_16(header + 28, fnsize);
-          WRITE_16(header + 30, extsize);
-          WRITE_16(header + 32, comsize);
-          WRITE_16(header + 34, 0);     /* disk # */
-          WRITE_16(header + 36, 0);     /* int attrb */
-          WRITE_32(header + 38, 0);     /* ext attrb */
-          WRITE_32(header + 42, currentOffset);
+          WRITE_32(central, 0x02014b50);
+          WRITE_16(central + 4, version);
+          WRITE_16(central + 6, version);
+          WRITE_16(central + 8, gpflag);
+          WRITE_16(central + 10, method);
+          WRITE_16(central + 12, filetime);
+          WRITE_16(central + 14, filedate);
+          WRITE_32(central + 16, crc);
+          WRITE_32(central + 20, cpsize);
+          WRITE_32(central + 24, uncpsize);
+          WRITE_16(central + 28, fnsize);
+          WRITE_16(central + 30, extsize);
+          WRITE_16(central + 32, comsize);
+          WRITE_16(central + 34, 0);    /* disk # */
+          WRITE_16(central + 36, 0);    /* int attrb */
+          WRITE_32(central + 38, 0);    /* ext attrb */
+          WRITE_32(central + 42, currentOffset);
           /* Header */
-          if (fwrite(header, 1, 46, fpOutCD) == 46) {
+          if (fwrite(central, 1, 46, fpOutCD) == 46) {
             offsetCD += 46;
 
             /* Filename */
@@ -215,23 +218,23 @@
     /* Final central directory  */
     {
       int entriesZip = entries;
-      char header[22];
+      char end[22];
       char* comment = ""; // "ZIP File recovered by zlib/minizip/mztools";
       int comsize = (int) strlen(comment);
       if (entriesZip > 0xffff) {
         entriesZip = 0xffff;
       }
-      WRITE_32(header, 0x06054b50);
-      WRITE_16(header + 4, 0);    /* disk # */
-      WRITE_16(header + 6, 0);    /* disk # */
-      WRITE_16(header + 8, entriesZip);   /* hack */
-      WRITE_16(header + 10, entriesZip);  /* hack */
-      WRITE_32(header + 12, offsetCD);    /* size of CD */
-      WRITE_32(header + 16, offset);      /* offset to CD */
-      WRITE_16(header + 20, comsize);     /* comment */
+      WRITE_32(end, 0x06054b50);
+      WRITE_16(end + 4, 0);         /* disk # */
+      WRITE_16(end + 6, 0);         /* disk # */
+      WRITE_16(end + 8, entriesZip);        /* hack */
+      WRITE_16(end + 10, entriesZip);       /* hack */
+      WRITE_32(end + 12, offsetCD);         /* size of CD */
+      WRITE_32(end + 16, offset);           /* offset to CD */
+      WRITE_16(end + 20, comsize);          /* comment */
 
       /* Header */
-      if (fwrite(header, 1, 22, fpOutCD) == 22) {
+      if (fwrite(end, 1, 22, fpOutCD) == 22) {
 
         /* Comment field */
         if (comsize > 0) {
diff --git a/contrib/minizip/unzip.c b/contrib/minizip/unzip.c
index feaec67..a2ee14b 100644
--- a/contrib/minizip/unzip.c
+++ b/contrib/minizip/unzip.c
@@ -1609,7 +1609,7 @@
                 uInt i;
                 for(i=0;i<uReadThis;i++)
                   pfile_in_zip_read_info->read_buffer[i] =
-                      zdecode(s->keys,s->pcrc_32_tab,
+                      (char)zdecode(s->keys,s->pcrc_32_tab,
                               pfile_in_zip_read_info->read_buffer[i]);
             }
 #            endif