egl/gallium: fix build without softpipe and llvmpipe
egl/gallium: fix build without softpipe and llvmpipe

Signed-off-by: Tobias Droste <6f0b7afb8e169bccf102c27c4328261728913687@gmx.de>
Acked-by: Jakob Bornecrantz <2a58f49788865949713c2d2b613178059f899d6a@gmail.com>
Reviewed-by: Marek Olšák <74bac9a67a04041c3586cda013cc5a11352e67be@gmail.com>

djreep81/glsl-optimizer,metora/MesaGLSLCompiler,benaadams/glsl-optimizer,zeux/glsl-optimizer,djreep81/glsl-optimizer,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,jbarczak/glsl-optimizer,metora/MesaGLSLCompiler,bkaradzic/glsl-optimizer,mcanthony/glsl-optimizer,djreep81/glsl-optimizer,zz85/glsl-optimizer,adobe/glsl2agal,KTXSoftware/glsl2agal,benaadams/glsl-optimizer,mcanthony/glsl-optimizer,tokyovigilante/glsl-optimizer,dellis1972/glsl-optimizer,adobe/glsl2agal,dellis1972/glsl-optimizer,metora/MesaGLSLCompiler,KTXSoftware/glsl2agal,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,bkaradzic/glsl-optimizer,zeux/glsl-optimizer,benaadams/glsl-optimizer,zeux/glsl-optimizer,bkaradzic/glsl-optimizer,mcanthony/glsl-optimizer,djreep81/glsl-optimizer,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,KTXSoftware/glsl2agal,zeux/glsl-optimizer,mapbox/glsl-optimizer,KTXSoftware/glsl2agal,adobe/glsl2agal,adobe/glsl2agal,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,djreep81/glsl-optimizer,mcanthony/glsl-optimizer,zeux/glsl-optimizer,zz85/glsl-optimizer,mapbox/glsl-optimizer,adobe/glsl2agal,wolf96/glsl-optimizer,tokyovigilante/glsl-optimizer,wolf96/glsl-optimizer,benaadams/glsl-optimizer,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,jbarczak/glsl-optimizer,zz85/glsl-optimizer,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,bkaradzic/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,wolf96/glsl-optimizer,jbarczak/glsl-optimizer,KTXSoftware/glsl2agal,mapbox/glsl-optimizer,tokyovigilante/glsl-optimizer,wolf96/glsl-optimizer,zz85/glsl-optimizer,wolf96/glsl-optimizer,mcanthony/glsl-optimizer