diff --git a/configure.in b/configure.in
index e5866ed9bd..4f44ea02ff 100644
--- a/configure.in
+++ b/configure.in
@@ -1729,7 +1729,7 @@ CPPFLAGS="$CPPFLAGS "'$(DEFS)'
 test -z "$CFLAGS" || CFLAGS="$CFLAGS "; CFLAGS="$CFLAGS"'${cflags}'
 test -z "$CPPFLAGS" || CPPFLAGS="$CPPFLAGS "; CPPFLAGS="$CPPFLAGS"'${cppflags}'
 AC_SUBST(cppflags, [])dnl
-AC_SUBST(cflags, ["${optflags} ${debugflags}"])dnl
+AC_SUBST(cflags, ['${optflags} ${debugflags}'])dnl
 AC_SUBST(optflags)dnl
 AC_SUBST(debugflags)dnl
 AC_SUBST(XCFLAGS)dnl