Don't implicitly export all symbols

In the old days, we used to export all symbols from a module by default.
We still do so, unless
o either exported symbols are explicitly listed in EXPORT_SYMBOL()
o or EXPORT_NO_SYMBOLS
is given.

This patches changes the default of 'export all symbols' to 'export no
symbols' for all files which are not listed in $(export-objs) in
the relevant Makefile.

include/linux/module.h

@@ -370,6 +370,8 @@ extern struct module *module_list;
 #define EXPORT_SYMBOL_NOVERS(var)  error this_object_must_be_defined_as_export_objs_in_the_Makefile
 #define EXPORT_SYMBOL_GPL(var)  error this_object_must_be_defined_as_export_objs_in_the_Makefile
 
+__asm__(".section __ksymtab,\"a\"\n.previous");
+
 #else
 
 #define __EXPORT_SYMBOL(sym, str)			\