Switch from using 'nacl_main' to 'main' entry point

ports/gdb/nacl.patch

Index: ports/gdb/nacl.patch
diff --git a/ports/gdb/nacl.patch b/ports/gdb/nacl.patch
index 879a76ac6ddb6691bfc35ebd27e533de25fd5536..128bddb1f55809e087a6d57945edba19c580ab7a 100644
--- a/ports/gdb/nacl.patch
+++ b/ports/gdb/nacl.patch
@@ -32,20 +32,6 @@ diff --git a/config/dfp.m4 b/config/dfp.m4
        enable_decimal_float=yes
        ;;
      *)
-diff --git a/gas/as.c b/gas/as.c
---- a/gas/as.c
-+++ b/gas/as.c
-@@ -1134,6 +1134,10 @@ create_obj_attrs_section (void)
- #endif
- 
- 
-+#ifdef __native_client__
-+int nacl_main(int argc, char ** argv);
-+#endif
-+
- int
- main (int argc, char ** argv)
- {
 diff --git a/gdb/charset.c b/gdb/charset.c
 --- a/gdb/charset.c
 +++ b/gdb/charset.c