linker: Make linker_{error,warning} generally available

linker_warning is a new function.  It's identical to linker_error
except that it doesn't set LinkStatus=false and it prepends "warning: "
on messages instead of "error: ".

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>

src/glsl/linker.h

@@ -25,9 +25,6 @@
 #ifndef GLSL_LINKER_H
 #define GLSL_LINKER_H
 
-extern void
-linker_error(gl_shader_program *prog, const char *fmt, ...);
-
 extern bool
 link_function_calls(gl_shader_program *prog, gl_shader *main,
 		    gl_shader **shader_list, unsigned num_shaders);