scons: Fix Haiku binary optimizations
scons: Fix Haiku binary optimizations

Haiku targets the Pentium or higher processor.
To ensure compatibility we can do march 586 and
mtune 686. Mesa will still use sse however if
the cpu supports it (and the stack is properly
aligned). These flags only effect the internal
compiler optimizations.

dellis1972/glsl-optimizer,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,mapbox/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,tokyovigilante/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,djreep81/glsl-optimizer,zeux/glsl-optimizer,bkaradzic/glsl-optimizer,zeux/glsl-optimizer,djreep81/glsl-optimizer,djreep81/glsl-optimizer,mcanthony/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,benaadams/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,metora/MesaGLSLCompiler,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,bkaradzic/glsl-optimizer,mcanthony/glsl-optimizer,zz85/glsl-optimizer,jbarczak/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer,dellis1972/glsl-optimizer,jbarczak/glsl-optimizer,metora/MesaGLSLCompiler,tokyovigilante/glsl-optimizer,mcanthony/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,dellis1972/glsl-optimizer,bkaradzic/glsl-optimizer,dellis1972/glsl-optimizer,bkaradzic/glsl-optimizer,dellis1972/glsl-optimizer,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,mcanthony/glsl-optimizer,mcanthony/glsl-optimizer,zz85/glsl-optimizer,benaadams/glsl-optimizer,wolf96/glsl-optimizer,benaadams/glsl-optimizer,mapbox/glsl-optimizer,jbarczak/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,mapbox/glsl-optimizer,metora/MesaGLSLCompiler,wolf96/glsl-optimizer,benaadams/glsl-optimizer,zz85/glsl-optimizer,zz85/glsl-optimizer