scons: Fix egl-static build due to conflicting symbols.
scons: Fix egl-static build due to conflicting symbols.

radeonsi and r600 have duplicate symbols, so it's not possible to
statically link both.  Remove the newcomer, radeonsi, until duplicate
symbols are fixed.

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