[PATCH] Fix __attribute__((hidden)) use

Hello, this patch fixes __attribute__ ((hidden)) use. The hidden_def(SYM)/hidden_proto(SYM) pair should be used for symbols that are a part of the public API; it creates hidden aliases (SYM_internal) for use within the shared library, which speeds up both dynamic linking and code execution. Symbols that are not in the public API should use "hidden" in the function declaration. This patch replaces all incorrect uses of hidden_def/hidden_proto by "hidden" (some uses in lib/private.h are left because these symbols used to be declared in libaudit.h). It also adds hidden_def/hidden_proto macros to those public symbols that are referenced from within the libraries. Mirek