diff --git a/Makefile b/Makefile
index 2ab7bc6c..c092c059 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ grafx2:
 ziprelease: grafx2
 	$(OPT)$(MAKE) -C src/ ziprelease
 
-tools:
+tools:	src/version.c
 	$(MAKE) -C tools/
 
 3rdparty:
@@ -37,3 +37,6 @@ doxygenarchive:
 # generate HTML doc to doc/html
 htmldoc:
 	$(MAKE) -C src/ htmldoc
+
+# this C file is generated by the build
+src/version.c:	grafx2
diff --git a/tools/Makefile b/tools/Makefile
index 315eb94a..a80943ad 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -1,6 +1,10 @@
 DOXYGEN = doxygen
 TAR = tar
 
+ifneq ($(shell test -f ../src/version.c && echo exists),exists)
+$(error please build grafx2 first. missing version.c file.)
+endif
+
 GIT_REVISION = $(shell cat ../src/version.c | cut -f 2 -d '"')
 LABEL = $(shell cat ../src/pversion.c | cut -f 2 -d '"')
 VERSION = $(subst wip.,wip,$(LABEL).$(GIT_REVISION))