Fix several issues in the preprocessor:

Fix several issues in the preprocessor:
 - macro expansion of hexidecimal numbers
 - give errors instead of warnings/silence on extra tokens after #endif, #else, etc.
 - give errors on reserved macro name use, reuse of argument, and redefinition with different whitespace presence
 - detect and give error for all cases of #elif and #else after #else

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@23982 e7fa87d3-cd2b-0410-9028-fcbf551c1848