Request 16-byte aligned stack with icc on x86_32

Originally committed as revision 25145 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -2898,6 +2898,7 @@ if enabled icc; then
     check_ldflags -march=$cpu
     # icc 11.0 and 11.1 work with ebp_available, but don't pass the test
     enable ebp_available
+    enabled x86_32 && check_cflags -falign-stack=maintain-16-byte
 elif enabled ccc; then
     # disable some annoying warnings
     add_cflags -msg_disable cvtu32to64