diff --git a/acinclude.m4 b/acinclude.m4
index f654e0f2..b1015e5a 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -368,8 +368,6 @@ AC_DEFUN([GB_INIT],
     AM_CXXFLAGS="$AM_CXXFLAGS -O0"
   fi
 
-  CFLAGS=""
-  CXXFLAGS=""
 
   AC_SUBST(AM_CFLAGS)
   AC_SUBST(AM_CFLAGS_OPT)
