Make TimeStamp 64-bit.

This prepares it for higher-resolution timestamps.
diff --git a/src/build_log.cc b/src/build_log.cc
index 333915a..a591050 100644
--- a/src/build_log.cc
+++ b/src/build_log.cc
@@ -353,7 +353,7 @@
 }
 
 bool BuildLog::WriteEntry(FILE* f, const LogEntry& entry) {
-  return fprintf(f, "%d\t%d\t%d\t%s\t%" PRIx64 "\n",
+  return fprintf(f, "%d\t%d\t%" PRId64 "\t%s\t%" PRIx64 "\n",
           entry.start_time, entry.end_time, entry.mtime,
           entry.output.c_str(), entry.command_hash) > 0;
 }
diff --git a/src/deps_log.cc b/src/deps_log.cc
index 89c6023..d7f0b26 100644
--- a/src/deps_log.cc
+++ b/src/deps_log.cc
@@ -30,7 +30,7 @@
 // The version is stored as 4 bytes after the signature and also serves as a
 // byte order mark. Signature and version combined are 16 bytes long.
 const char kFileSignature[] = "# ninjadeps\n";
-const int kCurrentVersion = 3;
+const int kCurrentVersion = 4;
 
 // Record size is currently limited to less than the full 32 bit, due to
 // internal buffers having to have this size.
@@ -124,7 +124,7 @@
     return true;
 
   // Update on-disk representation.
-  unsigned size = 4 * (1 + 1 + node_count);
+  unsigned size = 4 * (1 + 2 + node_count);
   if (size > kMaxRecordSize) {
     errno = ERANGE;
     return false;
@@ -135,8 +135,7 @@
   int id = node->id();
   if (fwrite(&id, 4, 1, file_) < 1)
     return false;
-  int timestamp = mtime;
-  if (fwrite(&timestamp, 4, 1, file_) < 1)
+  if (fwrite(&mtime, 8, 1, file_) < 1)
     return false;
   for (int i = 0; i < node_count; ++i) {
     id = nodes[i]->id();
@@ -218,9 +217,9 @@
       assert(size % 4 == 0);
       int* deps_data = reinterpret_cast<int*>(buf);
       int out_id = deps_data[0];
-      int mtime = deps_data[1];
-      deps_data += 2;
-      int deps_count = (size / 4) - 2;
+      TimeStamp mtime = reinterpret_cast<TimeStamp*>(&deps_data[1])[0];
+      deps_data += 3;
+      int deps_count = (size / 4) - 3;
 
       Deps* deps = new Deps(mtime, deps_count);
       for (int i = 0; i < deps_count; ++i) {
diff --git a/src/deps_log.h b/src/deps_log.h
index cec0257..793af07 100644
--- a/src/deps_log.h
+++ b/src/deps_log.h
@@ -57,7 +57,8 @@
 ///      one's complement of the expected index of the record (to detect
 ///      concurrent writes of multiple ninja processes to the log).
 ///    dependency records are an array of 4-byte integers
-///      [output path id, output path mtime, input path id, input path id...]
+///      [output path id, output path mtime (8-byte int), input path id,
+///       input path id...]
 ///      (The mtime is compared against the on-disk output path mtime
 ///      to verify the stored data is up-to-date.)
 /// If two records reference the same output the latter one in the file
@@ -75,10 +76,10 @@
 
   // Reading (startup-time) interface.
   struct Deps {
-    Deps(int mtime, int node_count)
+    Deps(int64_t mtime, int node_count)
         : mtime(mtime), node_count(node_count), nodes(new Node*[node_count]) {}
     ~Deps() { delete [] nodes; }
-    int mtime;
+    TimeStamp mtime;
     int node_count;
     Node** nodes;
   };
diff --git a/src/graph.cc b/src/graph.cc
index ce4ea77..b41c247 100644
--- a/src/graph.cc
+++ b/src/graph.cc
@@ -233,7 +233,7 @@
 
     if (output_mtime < most_recent_input->mtime()) {
       EXPLAIN("%soutput %s older than most recent input %s "
-              "(%d vs %d)",
+              "(%" PRId64 " vs %" PRId64 ")",
               used_restat ? "restat of " : "", output->path().c_str(),
               most_recent_input->path().c_str(),
               output_mtime, most_recent_input->mtime());
@@ -257,7 +257,7 @@
         // mtime of the most recent input.  This can occur even when the mtime
         // on disk is newer if a previous run wrote to the output file but
         // exited with an error or was interrupted.
-        EXPLAIN("recorded mtime of %s older than most recent input %s (%d vs %d)",
+        EXPLAIN("recorded mtime of %s older than most recent input %s (%" PRId64 " vs %" PRId64 ")",
                 output->path().c_str(), most_recent_input->path().c_str(),
                 entry->mtime, most_recent_input->mtime());
         return true;
@@ -441,7 +441,7 @@
 }
 
 void Node::Dump(const char* prefix) const {
-  printf("%s <%s 0x%p> mtime: %d%s, (:%s), ",
+  printf("%s <%s 0x%p> mtime: %" PRId64 "%s, (:%s), ",
          prefix, path().c_str(), this,
          mtime(), mtime() ? "" : " (:missing)",
          dirty() ? " dirty" : " clean");
@@ -547,7 +547,7 @@
 
   // Deps are invalid if the output is newer than the deps.
   if (output->mtime() > deps->mtime) {
-    EXPLAIN("stored deps info out of date for '%s' (%d vs %d)",
+    EXPLAIN("stored deps info out of date for '%s' (%" PRId64 " vs %" PRId64 ")",
             output->path().c_str(), deps->mtime, output->mtime());
     return false;
   }
diff --git a/src/ninja.cc b/src/ninja.cc
index ed004ac..a9030aa 100644
--- a/src/ninja.cc
+++ b/src/ninja.cc
@@ -494,7 +494,7 @@
     TimeStamp mtime = disk_interface.Stat((*it)->path(), &err);
     if (mtime == -1)
       Error("%s", err.c_str());  // Log and ignore Stat() errors;
-    printf("%s: #deps %d, deps mtime %d (%s)\n",
+    printf("%s: #deps %d, deps mtime %" PRId64 " (%s)\n",
            (*it)->path().c_str(), deps->node_count, deps->mtime,
            (!mtime || mtime > deps->mtime ? "STALE":"VALID"));
     for (int i = 0; i < deps->node_count; ++i)
diff --git a/src/timestamp.h b/src/timestamp.h
index cee7ba8..58ae148 100644
--- a/src/timestamp.h
+++ b/src/timestamp.h
@@ -17,8 +17,8 @@
 
 // When considering file modification times we only care to compare
 // them against one another -- we never convert them to an absolute
-// real time.  On POSIX we use time_t (seconds since epoch) and on
-// Windows we use a different value.  Both fit in an int.
-typedef int TimeStamp;
+// real time.  On POSIX we use timespec (seconds&nanoseconds since epoch)
+// and on Windows we use a different value.  Both fit in an int64.
+typedef int64_t TimeStamp;
 
 #endif  // NINJA_TIMESTAMP_H_
diff --git a/src/util.h b/src/util.h
index 4ee41a5..a8493d6 100644
--- a/src/util.h
+++ b/src/util.h
@@ -18,6 +18,7 @@
 #ifdef _WIN32
 #include "win32port.h"
 #else
+#include <inttypes.h>
 #include <stdint.h>
 #endif
 
diff --git a/src/win32port.h b/src/win32port.h
index ce3c949..5464797 100644
--- a/src/win32port.h
+++ b/src/win32port.h
@@ -23,6 +23,7 @@
 
 // printf format specifier for uint64_t, from C99.
 #ifndef PRIu64
+#define PRId64 "I64d"
 #define PRIu64 "I64u"
 #define PRIx64 "I64x"
 #endif