diff --git a/configure.ac b/configure.ac
index a2b4f3f9..98d45bca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -136,12 +136,12 @@ AC_ARG_WITH([jpeg7],
 AC_ARG_WITH([jpeg8],
     AC_HELP_STRING([--with-jpeg8], [Emulate libjpeg v8b API/ABI (this makes libjpeg-turbo backward incompatible with libjpeg v6b.)]))
 AC_MSG_CHECKING([libjpeg version number])
-if test "x${with_jpeg8}" == "xyes"; then
+if test "x${with_jpeg8}" = "xyes"; then
     JPEG_LIB_VERSION=80
     AC_DEFINE([JPEG_LIB_VERSION], [80], [Version 8.0])
     [JPEG_LIB_VERSION="`expr $JPEG_LIB_VERSION / 10`:2"]
 else
-    if test "x${with_jpeg7}" == "xyes"; then
+    if test "x${with_jpeg7}" = "xyes"; then
         JPEG_LIB_VERSION=70
         AC_DEFINE([JPEG_LIB_VERSION], [70], [Version 7.0])
         [JPEG_LIB_VERSION="`expr $JPEG_LIB_VERSION / 10`:`expr $JPEG_LIB_VERSION % 10`"]