Remove _mesa_memcpy in favor of plain memcpy.

This may break the SUNOS4 build, but it's no longer relevant.
diff --git a/src/mesa/shader/shader_api.c b/src/mesa/shader/shader_api.c
index 44310d2..7e2a60f 100644
--- a/src/mesa/shader/shader_api.c
+++ b/src/mesa/shader/shader_api.c
@@ -1380,7 +1380,7 @@
          GLchar *newName = _mesa_malloc(len + 1);
          if (!newName)
             return -1; /* out of mem */
-         _mesa_memcpy(newName, name, len);
+         memcpy(newName, name, len);
          newName[len] = 0;
 
          location = _mesa_lookup_uniform(shProg->Uniforms, newName);