glapi: fix bug with tls and relocs

add_dispatch (driver) and maybe get_proc_address (client) may be called before
set_dispatch is called, which results in generate_entrypoint using an unreloced
function template.

src/mesa/glapi/glapi_getproc.c

@@ -405,6 +405,7 @@ _glapi_add_dispatch( const char * const * function_names,
    unsigned i;
    int offset = ~0;
 
+   init_glapi_relocs_once();
 
    (void) memset( is_static, 0, sizeof( is_static ) );
    (void) memset( entry, 0, sizeof( entry ) );
@@ -533,6 +534,8 @@ _glapi_get_proc_address(const char *funcName)
    _glapi_proc func;
    struct _glapi_function * entry;
 
+   init_glapi_relocs_once();
+
 #ifdef MANGLE
    /* skip the prefix on the name */
    if (funcName[1] != 'g' || funcName[2] != 'l')