tcc -v displays short hash to ease detection of source version used to compile tcc

Makefile

@@ -24,6 +24,12 @@ CFLAGS += -I$(TOP)
 CFLAGS += $(CPPFLAGS)
 VPATH = $(TOPSRC)
 
+TCC_GIT_HASH=$(shell git rev-parse > /dev/null 2>&1 && git rev-parse --short HEAD || echo no)
+
+ifneq ($(TCC_GIT_HASH),no)
+ CFLAGS += -DTCC_GIT_HASH=\"$(TCC_GIT_HASH)\"
+endif
+
 ifdef CONFIG_WIN32
  CFG = -win
  ifneq ($(CONFIG_static),yes)

tcc.c

@@ -149,7 +149,13 @@ static const char help2[] =
     ;
 
 static const char version[] =
-    "tcc version "TCC_VERSION" ("
+    "tcc version "TCC_VERSION
+#ifdef TCC_GIT_HASH
+        " - " TCC_GIT_HASH
+#else
+        " - unknown hash"
+#endif
+    " ("
 #ifdef TCC_TARGET_I386
         "i386"
 #elif defined TCC_TARGET_X86_64