Switch to g_ for globals.

That's what the Google style guide recommends, and we're starting
to get a mix.

Change-Id: Ib0c53a890bb5deed5c679e887541a715faea91fc
diff --git a/linker/linker.h b/linker/linker.h
index 93ab51d..645498a 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -203,7 +203,7 @@
 ElfW(Sym)* dlsym_handle_lookup(soinfo* si, const char* name);
 
 void debuggerd_init();
-extern "C" abort_msg_t* gAbortMessage;
+extern "C" abort_msg_t* g_abort_message;
 extern "C" void notify_gdb_of_libraries();
 
 char* linker_get_error_buffer();