mesa: Fix some quirkiness of make tarballs
mesa: Fix some quirkiness of make tarballs

Among other benefits, parallel makes now work.  Since many people have
parallel builds by default (via MAKEFLAGS environment variable), this
sames some irritation at release time...when there's usually not any
other irritation already.

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