Add a proper test for VIS instruction support.

some help by Jan Knutar, jknutar nic fi

Originally committed as revision 10553 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -657,6 +657,7 @@ ARCH_EXT_LIST='
     mmi
     mmx
     ssse3
+    vis
 '
 
 HAVE_LIST="
@@ -726,6 +727,7 @@ iwmmxt_deps="armv4l"
 mmi_deps="mips"
 mmx_deps="x86"
 ssse3_deps="x86"
+vis_deps="sparc"
 
 # decoders / encoders
 ac3_decoder_deps="gpl"
@@ -1491,6 +1493,13 @@ int main(void) {
 }
 EOF
 
+# check VIS support
+enabled vis && check_cc -mcpu=ultrasparc <<EOF || disable vis
+int main(void) {
+    __asm__ __volatile__ ("pdist %f0, %f0, %f0");
+}
+EOF
+
 # ---
 # big/little-endian test
 check_cc <<EOF || die "endian test failed"