Make sure that the asm files don't incorrectly trigger an executable
stack marking in the final shared library.  That's bad, mmmkay.

before:
$ readelf -l /usr/lib/libsmpeg.so | grep -A 1 GNU_STACK
  GNU_STACK      0x0000000000000000 0x0000000000000000 0x0000000000000000
                 0x0000000000000000 0x0000000000000000  RWE    8
after:
$ readelf -l /usr/lib/libsmpeg.so | grep -A 1 GNU_STACK
  GNU_STACK      0x0000000000000000 0x0000000000000000 0x0000000000000000
                 0x0000000000000000 0x0000000000000000  RW     8

--- smpeg-0.4.4/video/mmxflags_asm.S
+++ smpeg-0.4.4/video/mmxflags_asm.S
@@ -57,3 +57,7 @@
 	.size	 cpu_flags,.Lfe1-cpu_flags
 
 #endif /* i386 && USE_MMX */
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif
--- smpeg-0.4.4/video/mmxidct_asm.S
+++ smpeg-0.4.4/video/mmxidct_asm.S
@@ -673,3 +673,7 @@
 
 
 #endif /* i386 && USE_MMX */
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif