Improve the build system to *properly* remove unnecessary symbols from the runtime global namespace. Along the way, change the prefixes on some internal-only API calls to use a common prefix.

With these changes, for a module to export symbols into the global namespace, it must have *both* the AST_MODFLAG_GLOBAL_SYMBOLS flag and a linker script that allows the linker to leave the symbols exposed in the module's .so file (see res_odbc.exports for an example).



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@182802 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/asterisk.exports

@@ -0,0 +1,28 @@
+{
+	global:
+		ast_*;
+		_ast_*;
+		__ast_*;
+		pbx_*;
+		astman_*;
+		ao2_*;
+		__ao2_*;
+		option_debug;
+		option_verbose;
+		dahdi_chan_name;
+		dahdi_chan_name_len;
+		dahdi_chan_mode;
+		cid_di;
+		cid_dr;
+		clidsb;
+		MD5*;
+		sched_*;
+		io_*;
+		jb_*;
+		channelreloadreason2txt;
+		devstate2str;
+		manager_event;
+		dialed_interface_info;
+	local:
+		*;
+};