check for ARM NEON assembler support

Originally committed as revision 13667 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -712,6 +712,7 @@ ARCH_EXT_LIST='
     mmi
     mmx
     mmx2
+    neon
     ssse3
     vis
 '
@@ -822,6 +823,7 @@ iwmmxt_deps="armv4l"
 mmi_deps="mips"
 mmx_deps="x86"
 mmx2_deps="x86 mmx"
+neon_deps="armv4l"
 ssse3_deps="x86"
 vis_deps="sparc"
 
@@ -1573,6 +1575,7 @@ enabled armv6   && check_asm armv6   '"sadd16 r0, r0, r0"'
 enabled armvfp  && check_asm armvfp  '"fadds s0, s0, s0"'
 enabled iwmmxt  && check_asm iwmmxt  '"wunpckelub wr6, wr4"'
 enabled mmi     && check_asm mmi     '"lq $2, 0($2)"'
+enabled neon    && check_asm neon    '"vadd.i16 q0, q0, q0"'
 enabled vis     && check_asm vis     '"pdist %f0, %f0, %f0"' -mcpu=ultrasparc
 
 enabled vis && add_cflags "-mcpu=ultrasparc -mtune=ultrasparc"
@@ -1934,6 +1937,7 @@ if test $arch = "armv4l"; then
     echo "ARMv6 enabled             ${armv6-no}"
     echo "ARM VFP enabled           ${armvfp-no}"
     echo "IWMMXT enabled            ${iwmmxt-no}"
+    echo "NEON enabled              ${neon-no}"
 fi
 if test $arch = "mips"; then
     echo "MMI enabled               ${mmi-no}"