Support the N_PEXT bit of the Mach-O object format....

third_party/yasm/patched-yasm/modules/objfmts/macho/macho-objfmt.c

 /*
  * Mac OS X ABI Mach-O File Format 
  *
  *  Copyright (C) 2007 Henryk Richter, built upon xdf objfmt (C) Peter Johnson
  *   
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 904 matching lines @@
                 intn = yasm_expr_get_intnum(csize, 1);
                 if (!intn) {
                     yasm_error_set(YASM_ERROR_NOT_CONSTANT,
                                    N_("COMMON data size not an integer expression"));
                     yasm_errwarn_propagate(info->errwarns, (*csize)->line);
                 } else
                     yasm_intnum_set_uint(val, yasm_intnum_get_uint(intn));
             }
             /*printf("common symbol %s val %lu\n", name, yasm_intnum_get_uint(val));*/
         } else if (vis & YASM_SYM_GLOBAL) {
-            n_type |= N_EXT;
+            yasm_valparamhead *valparams =
+                yasm_symrec_get_objext_valparams(sym);
+
+            struct macho_global_data {
+                unsigned long flag; /* N_PEXT */
+            } data;
+
+            data.flag = 0;
+
+            if (valparams) {
+                static const yasm_dir_help help[] = {
+                    { "private_extern", 0, yasm_dir_helper_flag_set,
+                      offsetof(struct macho_global_data, flag), N_PEXT },
+                };
+                yasm_dir_helper(sym, yasm_vps_first(valparams),
+                                yasm_symrec_get_decl_line(sym), help, NELEMS(help),
+                                &data, yasm_dir_helper_valparam_warn);
+            }
+
+            n_type |= N_EXT | data.flag;
         }
 
         localbuf = info->buf;
         YASM_WRITE_32_L(localbuf, info->indx);  /* offset in string table */
         YASM_WRITE_8(localbuf, n_type); /* type of symbol entry */
         n_sect = (scnum >= 0) ? scnum + 1 : NO_SECT;
         YASM_WRITE_8(localbuf, n_sect); /* referring section where symbol is found */
         YASM_WRITE_16_L(localbuf, n_desc);      /* extra description */
         yasm_intnum_get_sized(val, localbuf, long_int_bytes, ((long_int_bytes) << 3), 0, 0, 0); /* value/argument */
         localbuf += long_int_bytes;
@@ skipping 660 matching lines @@
     NULL,   /* no directives */
     NULL,   /* no standard macros */
     macho64_objfmt_create,
     macho_objfmt_output,
     macho_objfmt_destroy,
     macho_objfmt_add_default_section,
     macho_objfmt_init_new_section,
     macho_objfmt_section_switch,
     macho_objfmt_get_special_sym
 };