--- crack-attack-1.1.14/configure.ac
+++ crack-attack-1.1.14/configure.ac
@@ -75,10 +75,10 @@
     ],[found_sound=no]
   )
 
-  if test "$enable_sound" == "yes" -a "$found_sound" == "no"; then
+  if test "$enable_sound" = "yes" -a "$found_sound" = "no"; then
     AC_MSG_ERROR(libSDL and SDL_mixer are required for sound)
   fi
-  if test "$found_sound" == "yes"; then
+  if test "$found_sound" = "yes"; then
     AUDIO_CFLAGS="$SDL_CFLAGS"
     AUDIO_LIBS="$SDL_LIBS -lSDL_mixer"
     AC_DEFINE(AUDIO_ENABLED, 1, [Has audio support])