tools: do not regenerate nit_version.nit if not needed

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/git-gen-version.sh b/src/git-gen-version.sh
index 601b2b2..a165bc3 100755 (executable)
--- a/src/git-gen-version.sh
+++ b/src/git-gen-version.sh
@@ -20,12 +20,14 @@
 # The version number is stored in a dedicated Nit module.
 
 gen_version() {
-cat > nit_version.nit<<END
+       if ! grep "$*" nit_version.nit >/dev/null 2>&1; then
+               cat > nit_version.nit<<END
 # This file was generated by git-gen-version.sh
 package nit_version
 meth nit_version: String do return "$*"
 END
-echo "Version $*"
+               echo "Version $*"
+       fi
 }
 
 # Are we in the nitc.nit directory?