trackrdrd: -V emits a revision name derived from the git commit

(as in Varnish)

src/Makefile.am

@@ -2,15 +2,13 @@ INCLUDES = -I$(VARNISHSRC)/include -I$(VARNISHSRC)
 
 bin_PROGRAMS = trackrdrd
 
+nodist_trackrdrd_SOURCES = revision.h
+
 trackrdrd_SOURCES = \
+	trackrdrd.h \
 	trackrdrd.c \
 	parse.c \
 	log.c
-#	$(VARNISHSRC)/lib/libvarnish/assert.c \
-#	$(VARNISHSRC)/lib/libvarnish/flopen.c \
-#	$(VARNISHSRC)/lib/libvarnish/version.c \
-#	$(VARNISHSRC)/lib/libvarnish/vsb.c \
-#	$(VARNISHSRC)/lib/libvarnish/vpf.c
 
 trackrdrd_LDADD = \
 	$(VARNISHSRC)/lib/libvarnishcompat/libvarnishcompat.la \
@@ -20,3 +18,37 @@ trackrdrd_LDADD = \
 
 check:
 	test/regress.sh
+
+
+# Derive a revision name from the git commit
+# Adopted from Varnish include/Makefile.am
+BUILT_SOURCES = revision.h
+MAINTAINERCLEANFILES = revision.h 
+revision.h: FORCE
+	@if [ -d "$(top_srcdir)/../.git" ]; then \
+		V="$$(git show -s --pretty=format:%h)" \
+		H="$$(head -n 1 revision.h 2>/dev/null || true)"; \
+		if [ "/* $$V */" != "$$H" ]; then \
+		( \
+		  echo "/* $$V */" ;\
+		  echo '/*' ;\
+		  echo ' * NB:  This file is machine generated, DO NOT EDIT!' ;\
+		  echo ' *' ;\
+		  echo ' * Run make to regenerate' ;\
+		  echo ' *'  ;\
+		  echo ' */' ;\
+		  echo "/* $$V */" ;\
+		  echo '' ;\
+		  echo "#define REVISION \"$$V\"" \
+		) > revision.h ; \
+		fi \
+	else \
+		if [ ! -f revision.h ]; then \
+		( \
+		  echo "/* NOGIT */" ; \
+		  echo '/* No git commit ID available, see include/Makefile.am for explanation */' ; \
+		  echo '#define REVISION "NOGIT"' \
+		) >  revision.h ; \
+		fi \
+	fi
+FORCE:
\ No newline at end of file

src/trackrdrd.c

@@ -55,6 +55,7 @@
 #include "varnishapi.h"
 
 #include "trackrdrd.h"
+#include "revision.h"
 
 #define TRACK_TAGS "ReqStart,VCL_log,ReqEnd"
 #define TRACKLOG_PREFIX "track "
@@ -206,7 +207,7 @@ main(int argc, char * const *argv)
                     P_arg = optarg;
                     break;
 		case 'V':
-                    printf(PACKAGE_STRING "\n");
+                    printf(PACKAGE_STRING " revision " REVISION "\n");
                     exit(0);
                 case 'n':
                     if (VSL_Arg(vd, c, optarg) <= 0)