File fix-trunk_version-fallback.patch of Package gambas3

--- a/acinclude.m4
+++ b/acinclude.m4
@@ -128,6 +128,10 @@
     fi
   fi
 
+  if test "x${gb_vcs_version}" = "x" && test -r trunk_version.txt; then
+    gb_vcs_version="`cat trunk_version.txt`"
+  fi
+
   if test "x${gb_vcs_version}" != "x"; then
     AC_DEFINE_UNQUOTED(TRUNK_VERSION, "${gb_vcs_version}", [vcs revision])
     AC_MSG_RESULT([$gb_vcs_version])