Revising common/Makefile (issue #561, epic &29)

Signed-off-by: Adam Knapp <adam.knapp@ericsson.com>

common/Makefile

@@ -27,24 +27,16 @@ TOP := ..
 include $(TOP)/Makefile.cfg
 
 # Generating git_version.c according to GIT_COMMIT_ID
-ifeq ($(GIT_COMMIT_ID), yes)
-  $(shell echo -e "// this file was generated by make\n#include \"version_internal.h\"\n\nchar const *const GIT_COMMIT_ID = \"$$(git describe --always --dirty --match 'NOT A TAG')\";" > git_version.c.tmp; \
-  if [ ! -f git_version.c.tmp ]; then \
-    echo -e "// this file was generated by make\n#include \"version_internal.h\"\n\nchar const *const GIT_COMMIT_ID = \"\";" > git_version.c.tmp; \
-  fi; \
-  if diff -q git_version.c.tmp git_version.c >/dev/null 2>&1; then \
-    rm git_version.c.tmp; \
-  else \
-    mv git_version.c.tmp git_version.c; \
-  fi)
-else
-  $(shell echo -e "// this file was generated by make\n#include \"version_internal.h\"\n\nchar const *const GIT_COMMIT_ID = \"\";" > git_version.c.tmp; \
-  if diff -q git_version.c.tmp git_version.c >/dev/null 2>&1; then \
-    rm git_version.c.tmp; \
-  else \
-    mv git_version.c.tmp git_version.c; \
-  fi)
+GIT_HASH=`git describe --always --dirty --match 'NOT A TAG'`
+ifeq ($(GIT_COMMIT_ID), no)
+  GIT_HASH=""
 endif
+$(shell printf "// this file was generated by make\n#include \"version_internal.h\"\n\nchar const *const GIT_COMMIT_ID = \"${GIT_HASH}\";" > git_version.c.tmp)
+$(shell if diff -q git_version.c.tmp git_version.c >/dev/null 2>&1; then \
+  rm git_version.c.tmp; \
+else \
+  mv git_version.c.tmp git_version.c; \
+fi)
 
 TARGETS :=