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