X11: compile `GLXWorkstation` with OpenGL OpenGL compiler and linker flags are configured locally in `Make.proto` rather than in target config - this moves the configuration closer to the code. Currently all supported (and considered) platforms have OpenGL implementation. Later on one may use conditionals in makefile to deal exceptions.

LIBRARY         XWorkstat
DESCRIPTION     'Smalltalk/X X11 Display Interface'
VERSION         3.5
CODE            EXECUTE READ 
DATA            READ WRITE
SECTIONS
    INITCODE    READ EXECUTE 
    INITDATA    READ WRITE
EXPORTS 
    _XWorkstation_Init