Don't use non-POSIX test

test "$test_CFLAGS" == "" &&         \

may cause an error on some POSIX shells and uses a style which is not
consistent with the other tests in configure.ac

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=42588 and
https://bugs.gentoo.org/show_bug.cgi?id=387087

diff --git a/configure.ac b/configure.ac
index 79cf211..2eded70 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -150,7 +150,7 @@ AC_CHECK_DECL([__amd64], [AMD64_ABI="yes"], [AMD64_ABI="no"])
 # if we're using Sun Studio and neither the user nor a config.site
 # has set CFLAGS.
 if test $SUNCC = yes &&                        \
-   test "$test_CFLAGS" == "" &&                \
+   test "x$test_CFLAGS" = "x" &&       \
    test "$CFLAGS" = "-g"
 then
   CFLAGS="-O -g"