diff --git a/configure.py b/configure.py
index 84218b9..9ec368f 100755
--- a/configure.py
+++ b/configure.py
@@ -98,7 +98,7 @@
         return self._platform in ('freebsd', 'openbsd', 'bitrig')
 
     def supports_ppoll(self):
-        return self._platform in ('linux', 'openbsd', 'bitrig')
+        return self._platform in ('freebsd', 'linux', 'openbsd', 'bitrig')
 
     def supports_ninja_browse(self):
         return (not self.is_windows()
diff --git a/misc/measure.py b/misc/measure.py
index 1323fc6..8ce95e6 100755
--- a/misc/measure.py
+++ b/misc/measure.py
@@ -17,6 +17,8 @@
 """measure the runtime of a command by repeatedly running it.
 """
 
+from __future__ import print_function
+
 import time
 import subprocess
 import sys
@@ -24,7 +26,7 @@
 devnull = open('/dev/null', 'w')
 
 def run(cmd, repeat=10):
-    print 'sampling:',
+    print('sampling:', end=' ')
     sys.stdout.flush()
 
     samples = []
@@ -33,10 +35,10 @@
         subprocess.call(cmd, stdout=devnull, stderr=devnull)
         end = time.time()
         dt = (end - start) * 1000
-        print '%dms' % int(dt),
+        print('%dms' % int(dt), end=' ')
         sys.stdout.flush()
         samples.append(dt)
-    print
+    print()
 
     # We're interested in the 'pure' runtime of the code, which is
     # conceptually the smallest time we'd see if we ran it enough times
@@ -45,10 +47,10 @@
     # Also print how varied the outputs were in an attempt to make it
     # more obvious if something has gone terribly wrong.
     err = sum(s - best for s in samples) / float(len(samples))
-    print 'estimate: %dms (mean err %.1fms)' % (best, err)
+    print('estimate: %dms (mean err %.1fms)' % (best, err))
 
 if __name__ == '__main__':
     if len(sys.argv) < 2:
-        print 'usage: measure.py command args...'
+        print('usage: measure.py command args...')
         sys.exit(1)
     run(cmd=sys.argv[1:])
diff --git a/misc/write_fake_manifests.py b/misc/write_fake_manifests.py
index ca49535..b3594de 100644
--- a/misc/write_fake_manifests.py
+++ b/misc/write_fake_manifests.py
@@ -50,9 +50,10 @@
 
 
 class GenRandom(object):
-    def __init__(self):
+    def __init__(self, src_dir):
         self.seen_names = set([None])
         self.seen_defines = set([None])
+        self.src_dir = src_dir
 
     def _unique_string(self, seen, avg_options=1.3, p_suffix=0.1):
         s = None
@@ -76,7 +77,7 @@
 
     def src_obj_pairs(self, path, name):
         num_sources = paretoint(55, alpha=2) + 1
-        return [(os.path.join('..', '..', path, s + '.cc'),
+        return [(os.path.join(self.src_dir, path, s + '.cc'),
                  os.path.join('obj', path, '%s.%s.o' % (name, s)))
                 for s in self._n_unique_strings(num_sources)]
 
@@ -103,12 +104,8 @@
         self.kind = kind
         self.has_compile_depends = random.random() < 0.4
 
-    @property
-    def includes(self):
-        return ['-I' + dep.dir_path for dep in self.deps]
 
-
-def write_target_ninja(ninja, target):
+def write_target_ninja(ninja, target, src_dir):
     compile_depends = None
     if target.has_compile_depends:
       compile_depends = os.path.join(
@@ -117,8 +114,7 @@
       ninja.newline()
 
     ninja.variable('defines', target.defines)
-    if target.deps:
-        ninja.variable('includes', target.includes)
+    ninja.variable('includes', '-I' + src_dir)
     ninja.variable('cflags', ['-Wall', '-fno-rtti', '-fno-exceptions'])
     ninja.newline()
 
@@ -129,17 +125,63 @@
     deps = [dep.output for dep in target.deps]
     libs = [dep.output for dep in target.deps if dep.kind == LIB]
     if target.kind == EXE:
-        ninja.variable('ldflags', '-Wl,pie')
         ninja.variable('libs', libs)
+        if sys.platform == "darwin":
+            ninja.variable('ldflags', '-Wl,-pie')
     link = { LIB: 'alink', EXE: 'link'}[target.kind]
     ninja.build(target.output, link, [obj for _, obj in target.src_obj_pairs],
                 implicit=deps)
 
 
+def write_sources(target, root_dir):
+    need_main = target.kind == EXE
+
+    includes = []
+
+    # Include siblings.
+    for cc_filename, _ in target.src_obj_pairs:
+        h_filename = os.path.basename(os.path.splitext(cc_filename)[0] + '.h')
+        includes.append(h_filename)
+
+    # Include deps.
+    for dep in target.deps:
+        for cc_filename, _ in dep.src_obj_pairs:
+            h_filename = os.path.basename(
+                os.path.splitext(cc_filename)[0] + '.h')
+            includes.append("%s/%s" % (dep.dir_path, h_filename))
+
+    for cc_filename, _ in target.src_obj_pairs:
+        cc_path = os.path.join(root_dir, cc_filename)
+        h_path = os.path.splitext(cc_path)[0] + '.h'
+        namespace = os.path.basename(target.dir_path)
+        class_ = os.path.splitext(os.path.basename(cc_filename))[0]
+        try:
+            os.makedirs(os.path.dirname(cc_path))
+        except OSError:
+            pass
+
+        with open(h_path, 'w') as f:
+            f.write('namespace %s { struct %s { %s(); }; }' % (namespace,
+                                                               class_, class_))
+        with open(cc_path, 'w') as f:
+            for include in includes:
+                f.write('#include "%s"\n' % include)
+            f.write('\n')
+            f.write('namespace %s { %s::%s() {} }' % (namespace,
+                                                      class_, class_))
+
+            if need_main:
+                f.write('int main(int argc, char **argv) {}\n')
+                need_main = False
+
 def write_master_ninja(master_ninja, targets):
     """Writes master build.ninja file, referencing all given subninjas."""
     master_ninja.variable('cxx', 'c++')
     master_ninja.variable('ld', '$cxx')
+    if sys.platform == 'darwin':
+        master_ninja.variable('alink', 'libtool -static')
+    else:
+        master_ninja.variable('alink', 'ar rcs')
     master_ninja.newline()
 
     master_ninja.pool('link_pool', depth=4)
@@ -148,8 +190,8 @@
     master_ninja.rule('cxx', description='CXX $out',
       command='$cxx -MMD -MF $out.d $defines $includes $cflags -c $in -o $out',
       depfile='$out.d', deps='gcc')
-    master_ninja.rule('alink', description='LIBTOOL-STATIC $out',
-      command='rm -f $out && libtool -static -o $out $in')
+    master_ninja.rule('alink', description='ARCHIVE $out',
+      command='rm -f $out && $alink -o $out $in')
     master_ninja.rule('link', description='LINK $out', pool='link_pool',
       command='$ld $ldflags -o $out $in $libs')
     master_ninja.rule('stamp', description='STAMP $out', command='touch $out')
@@ -181,9 +223,8 @@
     f.close()
 
 
-def random_targets():
-    num_targets = 1500
-    gen = GenRandom()
+def random_targets(num_targets, src_dir):
+    gen = GenRandom(src_dir)
 
     # N-1 static libraries, and 1 executable depending on all of them.
     targets = [Target(gen, LIB) for i in xrange(num_targets - 1)]
@@ -199,16 +240,28 @@
 
 def main():
     parser = argparse.ArgumentParser()
+    parser.add_argument('-s', '--sources', nargs="?", const="src",
+        help='write sources to directory (relative to output directory)')
+    parser.add_argument('-t', '--targets', type=int, default=1500,
+                        help='number of targets (default: 1500)')
+    parser.add_argument('-S', '--seed', type=int, help='random seed',
+                        default=12345)
     parser.add_argument('outdir', help='output directory')
     args = parser.parse_args()
     root_dir = args.outdir
 
-    random.seed(12345)
+    random.seed(args.seed)
 
-    targets = random_targets()
+    do_write_sources = args.sources is not None
+    src_dir = args.sources if do_write_sources else "src"
+
+    targets = random_targets(args.targets, src_dir)
     for target in targets:
         with FileWriter(os.path.join(root_dir, target.ninja_file_path)) as n:
-            write_target_ninja(n, target)
+            write_target_ninja(n, target, src_dir)
+
+        if do_write_sources:
+            write_sources(target, root_dir)
 
     with FileWriter(os.path.join(root_dir, 'build.ninja')) as master_ninja:
         master_ninja.width = 120
diff --git a/src/browse.py b/src/browse.py
index 32792f3..4b4faa8 100755
--- a/src/browse.py
+++ b/src/browse.py
@@ -27,6 +27,7 @@
 except ImportError:
     import BaseHTTPServer as httpserver
 import argparse
+import cgi
 import os
 import socket
 import subprocess
@@ -58,6 +59,9 @@
         return (False, line)
     return (True, line[len(prefix):])
 
+def html_escape(text):
+    return cgi.escape(text, quote=True)
+
 def parse(text):
     lines = iter(text.split('\n'))
 
@@ -124,19 +128,19 @@
 ''' + body
 
 def generate_html(node):
-    document = ['<h1><tt>%s</tt></h1>' % node.target]
+    document = ['<h1><tt>%s</tt></h1>' % html_escape(node.target)]
 
     if node.inputs:
         document.append('<h2>target is built using rule <tt>%s</tt> of</h2>' %
-                        node.rule)
+                        html_escape(node.rule))
         if len(node.inputs) > 0:
             document.append('<div class=filelist>')
             for input, type in sorted(node.inputs):
                 extra = ''
                 if type:
-                    extra = ' (%s)' % type
+                    extra = ' (%s)' % html_escape(type)
                 document.append('<tt><a href="?%s">%s</a>%s</tt><br>' %
-                                (input, input, extra))
+                                (html_escape(input), html_escape(input), extra))
             document.append('</div>')
 
     if node.outputs:
@@ -144,7 +148,7 @@
         document.append('<div class=filelist>')
         for output in sorted(node.outputs):
             document.append('<tt><a href="?%s">%s</a></tt><br>' %
-                            (output, output))
+                            (html_escape(output), html_escape(output)))
         document.append('</div>')
 
     return '\n'.join(document)
@@ -177,7 +181,7 @@
             page_body = generate_html(parse(ninja_output.strip()))
         else:
             # Relay ninja's error message.
-            page_body = '<h1><tt>%s</tt></h1>' % ninja_error
+            page_body = '<h1><tt>%s</tt></h1>' % html_escape(ninja_error)
 
         self.send_response(200)
         self.end_headers()
diff --git a/src/build.cc b/src/build.cc
index 8c0fbf8..64710dd 100644
--- a/src/build.cc
+++ b/src/build.cc
@@ -97,7 +97,7 @@
   ++started_edges_;
 
   if (edge->use_console() || printer_.is_smart_terminal())
-    PrintStatus(edge);
+    PrintStatus(edge, kEdgeStarted);
 
   if (edge->use_console())
     printer_.SetConsoleLocked(true);
@@ -109,6 +109,7 @@
                                     int* start_time,
                                     int* end_time) {
   int64_t now = GetTimeMillis();
+
   ++finished_edges_;
 
   RunningEdgeMap::iterator i = running_edges_.find(edge);
@@ -123,7 +124,7 @@
     return;
 
   if (!edge->use_console())
-    PrintStatus(edge);
+    PrintStatus(edge, kEdgeFinished);
 
   // Print the command that is spewing before printing its output.
   if (!success) {
@@ -158,13 +159,18 @@
   }
 }
 
+void BuildStatus::BuildStarted() {
+  overall_rate_.Restart();
+  current_rate_.Restart();
+}
+
 void BuildStatus::BuildFinished() {
   printer_.SetConsoleLocked(false);
   printer_.PrintOnNewLine("");
 }
 
 string BuildStatus::FormatProgressStatus(
-    const char* progress_status_format) const {
+    const char* progress_status_format, EdgeStatus status) const {
   string out;
   char buf[32];
   int percent;
@@ -189,10 +195,15 @@
         break;
 
         // Running edges.
-      case 'r':
-        snprintf(buf, sizeof(buf), "%d", started_edges_ - finished_edges_);
+      case 'r': {
+        int running_edges = started_edges_ - finished_edges_;
+        // count the edge that just finished as a running edge
+        if (status == kEdgeFinished)
+          running_edges++;
+        snprintf(buf, sizeof(buf), "%d", running_edges);
         out += buf;
         break;
+      }
 
         // Unstarted edges.
       case 'u':
@@ -209,14 +220,14 @@
         // Overall finished edges per second.
       case 'o':
         overall_rate_.UpdateRate(finished_edges_);
-        snprinfRate(overall_rate_.rate(), buf, "%.1f");
+        SnprintfRate(overall_rate_.rate(), buf, "%.1f");
         out += buf;
         break;
 
         // Current rate, average over the last '-j' jobs.
       case 'c':
         current_rate_.UpdateRate(finished_edges_);
-        snprinfRate(current_rate_.rate(), buf, "%.1f");
+        SnprintfRate(current_rate_.rate(), buf, "%.1f");
         out += buf;
         break;
 
@@ -246,7 +257,7 @@
   return out;
 }
 
-void BuildStatus::PrintStatus(Edge* edge) {
+void BuildStatus::PrintStatus(Edge* edge, EdgeStatus status) {
   if (config_.verbosity == BuildConfig::QUIET)
     return;
 
@@ -256,11 +267,7 @@
   if (to_print.empty() || force_full_command)
     to_print = edge->GetBinding("command");
 
-  if (finished_edges_ == 0) {
-    overall_rate_.Restart();
-    current_rate_.Restart();
-  }
-  to_print = FormatProgressStatus(progress_status_format_) + to_print;
+  to_print = FormatProgressStatus(progress_status_format_, status) + to_print;
 
   printer_.Print(to_print,
                  force_full_command ? LinePrinter::FULL : LinePrinter::ELIDE);
@@ -643,6 +650,9 @@
       command_runner_.reset(new RealCommandRunner(config_));
   }
 
+  // We are about to start the build process.
+  status_->BuildStarted();
+
   // This main loop runs the entire build process.
   // It is structured like this:
   // First, we attempt to start as many commands as allowed by the
diff --git a/src/build.h b/src/build.h
index 51589ef..66ce607 100644
--- a/src/build.h
+++ b/src/build.h
@@ -200,16 +200,24 @@
   void BuildEdgeStarted(Edge* edge);
   void BuildEdgeFinished(Edge* edge, bool success, const string& output,
                          int* start_time, int* end_time);
+  void BuildStarted();
   void BuildFinished();
 
+  enum EdgeStatus {
+    kEdgeStarted,
+    kEdgeFinished,
+  };
+
   /// Format the progress status string by replacing the placeholders.
   /// See the user manual for more information about the available
   /// placeholders.
   /// @param progress_status_format The format of the progress status.
-  string FormatProgressStatus(const char* progress_status_format) const;
+  /// @param status The status of the edge.
+  string FormatProgressStatus(const char* progress_status_format,
+                              EdgeStatus status) const;
 
  private:
-  void PrintStatus(Edge* edge);
+  void PrintStatus(Edge* edge, EdgeStatus status);
 
   const BuildConfig& config_;
 
@@ -229,9 +237,11 @@
   const char* progress_status_format_;
 
   template<size_t S>
-  void snprinfRate(double rate, char(&buf)[S], const char* format) const {
-    if (rate == -1) snprintf(buf, S, "?");
-    else            snprintf(buf, S, format, rate);
+  void SnprintfRate(double rate, char(&buf)[S], const char* format) const {
+    if (rate == -1)
+      snprintf(buf, S, "?");
+    else
+      snprintf(buf, S, format, rate);
   }
 
   struct RateInfo {
diff --git a/src/build_test.cc b/src/build_test.cc
index 55d093e..640e1b0 100644
--- a/src/build_test.cc
+++ b/src/build_test.cc
@@ -1286,7 +1286,8 @@
   ASSERT_EQ("", err);
   EXPECT_TRUE(builder_.Build(&err));
   ASSERT_EQ("", err);
-  EXPECT_EQ("[3/3]", builder_.status_->FormatProgressStatus("[%s/%t]"));
+  EXPECT_EQ("[3/3]", builder_.status_->FormatProgressStatus("[%s/%t]",
+      BuildStatus::kEdgeStarted));
   command_runner_.commands_ran_.clear();
   state_.Reset();
 
@@ -1724,9 +1725,18 @@
   ASSERT_EQ(1u, command_runner_.commands_ran_.size());
 }
 
+TEST_F(BuildTest, StatusFormatElapsed) {
+  status_.BuildStarted();
+  // Before any task is done, the elapsed time must be zero.
+  EXPECT_EQ("[%/e0.000]",
+            status_.FormatProgressStatus("[%%/e%e]",
+                BuildStatus::kEdgeStarted));
+}
+
 TEST_F(BuildTest, StatusFormatReplacePlaceholder) {
   EXPECT_EQ("[%/s0/t0/r0/u0/f0]",
-            status_.FormatProgressStatus("[%%/s%s/t%t/r%r/u%u/f%f]"));
+            status_.FormatProgressStatus("[%%/s%s/t%t/r%r/u%u/f%f]",
+                BuildStatus::kEdgeStarted));
 }
 
 TEST_F(BuildTest, FailedDepsParse) {
diff --git a/src/graph_test.cc b/src/graph_test.cc
index 723e8ea..be08b19 100644
--- a/src/graph_test.cc
+++ b/src/graph_test.cc
@@ -149,6 +149,45 @@
   EXPECT_TRUE(GetNode("out.imp")->dirty());
 }
 
+TEST_F(GraphTest, ImplicitOutputOnlyParse) {
+  ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
+"build | out.imp: cat in\n"));
+
+  Edge* edge = GetNode("out.imp")->in_edge();
+  EXPECT_EQ(1, edge->outputs_.size());
+  EXPECT_EQ("out.imp", edge->outputs_[0]->path());
+  EXPECT_EQ(1, edge->implicit_outs_);
+  EXPECT_EQ(edge, GetNode("out.imp")->in_edge());
+}
+
+TEST_F(GraphTest, ImplicitOutputOnlyMissing) {
+  ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
+"build | out.imp: cat in\n"));
+  fs_.Create("in", "");
+
+  Edge* edge = GetNode("out.imp")->in_edge();
+  string err;
+  EXPECT_TRUE(scan_.RecomputeDirty(edge, &err));
+  ASSERT_EQ("", err);
+
+  EXPECT_TRUE(GetNode("out.imp")->dirty());
+}
+
+TEST_F(GraphTest, ImplicitOutputOnlyOutOfDate) {
+  ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
+"build | out.imp: cat in\n"));
+  fs_.Create("out.imp", "");
+  fs_.Tick();
+  fs_.Create("in", "");
+
+  Edge* edge = GetNode("out.imp")->in_edge();
+  string err;
+  EXPECT_TRUE(scan_.RecomputeDirty(edge, &err));
+  ASSERT_EQ("", err);
+
+  EXPECT_TRUE(GetNode("out.imp")->dirty());
+}
+
 TEST_F(GraphTest, PathWithCurrentDirectory) {
   ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
 "rule catdep\n"
diff --git a/src/manifest_parser.cc b/src/manifest_parser.cc
index a4f489e..d6dcf22 100644
--- a/src/manifest_parser.cc
+++ b/src/manifest_parser.cc
@@ -236,16 +236,13 @@
     EvalString out;
     if (!lexer_.ReadPath(&out, err))
       return false;
-    if (out.empty())
-      return lexer_.Error("expected path", err);
-
-    do {
+    while (!out.empty()) {
       outs.push_back(out);
 
       out.Clear();
       if (!lexer_.ReadPath(&out, err))
         return false;
-    } while (!out.empty());
+    }
   }
 
   // Add all implicit outs, counting how many as we go.
@@ -262,6 +259,9 @@
     }
   }
 
+  if (outs.empty())
+    return lexer_.Error("expected path", err);
+
   if (!ExpectToken(Lexer::COLON, err))
     return false;
 
diff --git a/src/manifest_parser_test.cc b/src/manifest_parser_test.cc
index 1312d26..3c82dc5 100644
--- a/src/manifest_parser_test.cc
+++ b/src/manifest_parser_test.cc
@@ -976,13 +976,10 @@
 TEST_F(ParserTest, NoExplicitOutput) {
   ManifestParser parser(&state, NULL, kDupeEdgeActionWarn);
   string err;
-  EXPECT_FALSE(parser.ParseTest(
+  EXPECT_TRUE(parser.ParseTest(
 "rule cat\n"
 "  command = cat $in > $out\n"
 "build | imp : cat bar\n", &err));
-  ASSERT_EQ("input:3: expected path\n"
-            "build | imp : cat bar\n"
-            "      ^ near here", err);
 }
 
 TEST_F(ParserTest, DefaultDefault) {
diff --git a/src/state.cc b/src/state.cc
index a70f211..d539e7b 100644
--- a/src/state.cc
+++ b/src/state.cc
@@ -159,11 +159,12 @@
   return true;
 }
 
-vector<Node*> State::RootNodes(string* err) {
+vector<Node*> State::RootNodes(string* err) const {
   vector<Node*> root_nodes;
   // Search for nodes with no output.
-  for (vector<Edge*>::iterator e = edges_.begin(); e != edges_.end(); ++e) {
-    for (vector<Node*>::iterator out = (*e)->outputs_.begin();
+  for (vector<Edge*>::const_iterator e = edges_.begin();
+       e != edges_.end(); ++e) {
+    for (vector<Node*>::const_iterator out = (*e)->outputs_.begin();
          out != (*e)->outputs_.end(); ++out) {
       if ((*out)->out_edges().empty())
         root_nodes.push_back(*out);
@@ -176,7 +177,7 @@
   return root_nodes;
 }
 
-vector<Node*> State::DefaultNodes(string* err) {
+vector<Node*> State::DefaultNodes(string* err) const {
   return defaults_.empty() ? RootNodes(err) : defaults_;
 }
 
diff --git a/src/state.h b/src/state.h
index d7987ba..b530207 100644
--- a/src/state.h
+++ b/src/state.h
@@ -110,8 +110,8 @@
 
   /// @return the root node(s) of the graph. (Root nodes have no output edges).
   /// @param error where to write the error message if somethings went wrong.
-  vector<Node*> RootNodes(string* error);
-  vector<Node*> DefaultNodes(string* error);
+  vector<Node*> RootNodes(string* error) const;
+  vector<Node*> DefaultNodes(string* error) const;
 
   /// Mapping of path -> Node.
   typedef ExternalStringHashMap<Node*>::Type Paths;
diff --git a/src/subprocess.h b/src/subprocess.h
index 51f40b2..b2d486c 100644
--- a/src/subprocess.h
+++ b/src/subprocess.h
@@ -26,6 +26,14 @@
 #include <signal.h>
 #endif
 
+// ppoll() exists on FreeBSD, but only on newer versions.
+#ifdef __FreeBSD__
+#  include <sys/param.h>
+#  if defined USE_PPOLL && __FreeBSD_version < 1002000
+#    undef USE_PPOLL
+#  endif
+#endif
+
 #include "exit_status.h"
 
 /// Subprocess wraps a single async subprocess.  It is entirely
diff --git a/src/subprocess_test.cc b/src/subprocess_test.cc
index ee16190..0a8c206 100644
--- a/src/subprocess_test.cc
+++ b/src/subprocess_test.cc
@@ -214,9 +214,7 @@
   }
 }
 
-// OS X's process limit is less than 1025 by default
-// (|sysctl kern.maxprocperuid| is 709 on 10.7 and 10.8 and less prior to that).
-#if !defined(__APPLE__) && !defined(_WIN32)
+#if defined(USE_PPOLL)
 TEST_F(SubprocessTest, SetWithLots) {
   // Arbitrary big number; needs to be over 1024 to confirm we're no longer
   // hostage to pselect.
diff --git a/src/version.cc b/src/version.cc
index a048a18..eafa082 100644
--- a/src/version.cc
+++ b/src/version.cc
@@ -18,7 +18,7 @@
 
 #include "util.h"
 
-const char* kNinjaVersion = "1.7.1";
+const char* kNinjaVersion = "1.7.2";
 
 void ParseVersion(const string& version, int* major, int* minor) {
   size_t end = version.find('.');