Clean up unnecessary compiler.h preprocessor madness

[rcurtin]

Reported by rcurtin on 24 Nov 40302814 14:13 UTC
Most of the stuff in base/compiler.h is of the form:

#ifdef NO_COMPILER_DEFS
#define SOME_ATTRIBUTE __attribute__((something))
#else
#define SOME_ATTRIBUTE
#endif

Watch this:

#ifndef __GNUC__
#define __attribute__(x) 
#endif

And bam, the problem is solved. This should be done to remove most of the random #define statements, make code a little less confusing, and prune down compiler.h to an absolute minimum.