diff --git a/src/build_log.cc b/src/build_log.cc
index a591050..648617c 100644
--- a/src/build_log.cc
+++ b/src/build_log.cc
@@ -290,7 +290,7 @@
     if (!end)
       continue;
     *end = 0;
-    restat_mtime = atol(start);
+    restat_mtime = strtoll(start, NULL, 10);
     start = end + 1;
 
     end = (char*)memchr(start, kFieldSeparator, line_end - start);