Prefix error messages with program name.

It make it easier while debugging to know who is reporting the error:
Ninja itself or one of the command called by Ninja during the build
process or one of the generator which called Ninja.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/util.cc b/src/util.cc
index 1968702..a2e080f 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -20,10 +20,19 @@
 
 void Fatal(const char* msg, ...) {
   va_list ap;
-  fprintf(stderr, "FATAL: ");
+  fprintf(stderr, "ninja: FATAL: ");
   va_start(ap, msg);
   vfprintf(stderr, msg, ap);
   va_end(ap);
   fprintf(stderr, "\n");
   exit(1);
 }
+
+void Error(const char* msg, ...) {
+  va_list ap;
+  fprintf(stderr, "ninja: error: ");
+  va_start(ap, msg);
+  vfprintf(stderr, msg, ap);
+  va_end(ap);
+  fprintf(stderr, "\n");
+}