:: commit 916717cce2bb99dba2b1ab0d188c5d07167b0819

diff --git a/configure.ac b/configure.ac
index 351dc19..2d7327a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -9,7 +9,7 @@ AC_PROG_CC([clang gcc icc])
 LT_INIT
 
 AC_MSG_CHECKING([whether system or user specificed compiler flags are set])
-AM_CONDITIONAL([PASSED_CFLAGS], [test -z "$CFLAGS"])
+AM_CONDITIONAL([PASSED_CFLAGS], [test -n "$CFLAGS"])
 AM_COND_IF([PASSED_CFLAGS], [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([no])])
 
 AC_ARG_WITH([pthread],