[PATCH] remove target dependency for atomicity.h on ix86

[Matthias Klose]

Benjamin Kosnik writes:
> 
> What problem are you trying to solve? 

two problems:

- having a compiler configured for i386-linux, it's not possible to
  use the i486 implemention when using -march=i486 (or above).

- having a libstdc++ built for i386-linux in /usr/lib and one
  for i486 in /usr/lib/i486 (and the dynamic linker chooses
  the latter on a i486 host), you get an error for:

	#include <string>

	int main()
	{
	    std::string bleh;
	    return 0;
	}

  g++-3.3 -O2 -o test test.cc ; ./test
  ./test: relocation error: ./test: symbol _ZN9__gnu_cxx17_Atomic_add_mutexE, version GLIBCPP_3.2.3 not defined in file libstdc++.so.5 with link time reference