configure: fix arch x86_32

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -2294,7 +2294,7 @@ case "$arch" in
         arch="sparc"
         subarch="sparc64"
     ;;
-    i[3-6]86|i86pc|BePC|x86pc|x86_64|amd64)
+    i[3-6]86|i86pc|BePC|x86pc|x86_64|x86_32|amd64)
         arch="x86"
     ;;
 esac