--- configure.ac.orig	2018-12-13 10:20:53 UTC
+++ configure.ac
@@ -658,7 +658,7 @@ AH_BOTTOM([
 #endif
 
 #if !defined(CUSTOM_STRING) && defined(COMPILER_STRING)
-#define CUSTOM_STRING PACKAGE_STRING" "SVN_REV" "COMPILER_STRING
+#define CUSTOM_STRING PACKAGE_STRING " " SVN_REV " " COMPILER_STRING
 #endif
 
 #include "std_fixes.h"
