Test for Altivec C extensions.

configure.in

@@ -259,6 +259,16 @@ if test x"$ac_cv_altivec_inline" != x"no"; then
   ACCEL_MODULES="${ACCEL_MODULES} ${ALTIVEC_MODULES}"
 fi
 
+AC_CACHE_CHECK([if \$CC groks Altivec C extensions],
+    [ac_cv_c_altivec],
+    [save_CFLAGS=$CFLAGS; CFLAGS="$CFLAGS -faltivec"
+     AC_TRY_COMPILE([void quux(){vec_mtvscr((vector unsigned int)(0));}],,
+        ac_cv_c_altivec=yes, ac_cv_c_altivec=no)
+     CFLAGS=$save_CFLAGS])
+if test x"$ac_cv_c_altivec" != x"no"; then
+  AC_DEFINE(HAVE_C_ALTIVEC, 1, Define if your compiler groks C altivec extensions.)
+fi
+
 dnl
 dnl  libdvdcss: check for DVD ioctls
 dnl

include/defs.h.in

@@ -196,6 +196,9 @@
 /* Maximum supported data alignment */
 #undef ATTRIBUTE_ALIGNED_MAX
 
+/* Define if your compiler groks C altivec extensions. */
+#undef HAVE_C_ALTIVEC
+
 /* Define if <sys/dvdio.h> defines dvd_struct. */
 #undef DVD_STRUCT_IN_SYS_DVDIO_H