Close memory leak in lexer.
Close memory leak in lexer.

Simply call talloc_strdup rather than strdup, (using the talloc_parent
of our 'state' object, (known here as yyextra).

This fix now makes glsl-orangebook-ch06-bump.frag 99.97% leak free:

	total heap usage: 55,623 allocs, 55,609 frees

Only 14 missing frees now.

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