Windows resource: handle dashes in the Git version gracefully

Reported by postiffm as issue #14.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>

Makefile

@@ -1777,7 +1777,7 @@ $(SCRIPT_LIB) : % : %.sh GIT-SCRIPT-DEFINES
 
 git.res: git.rc
 	$(QUIET_RC)$(RC) \
-	  $(join -DMAJOR= -DMINOR= -DPATCH=, $(wordlist 1,3,$(subst ., ,$(GIT_VERSION)))) \
+	  $(join -DMAJOR= -DMINOR= -DPATCH=, $(wordlist 1,3,$(subst -, ,$(subst ., ,$(GIT_VERSION))))) \
 	  -DGIT_VERSION="\\\"$(GIT_VERSION)\\\"" $< -o $@
 
 ifndef NO_PERL