glsl: fix new gcc6 warnings
glsl: fix new gcc6 warnings

src/compiler/glsl/ast_to_hir.cpp: In function ‘unsigned int ast_process_struct_or_iface_block_members(exec_list*, _mesa_glsl_parse_state*, exec_list*, glsl_struct_field**, bool, glsl_matrix_layout, bool, ir_variable_mode, ast_type_qualifier*,
unsigned int, unsigned int)’:
src/compiler/glsl/ast_to_hir.cpp:6339:52: warning: ‘first_member_has_explicit_location’ may be used uninitialized in this function [-Wmaybe-uninitialized]
             if (!layout->flags.q.explicit_location &&
                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
                 ((first_member_has_explicit_location &&
                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                   !qual->flags.q.explicit_location) ||
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                  (!first_member_has_explicit_location &&
                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                   qual->flags.q.explicit_location))) {
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Rob Clark <915c10c999604870200b6defbe633d857c856ca0@gmail.com>
Reviewed-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler