Use top_srcdir instead of top_builddir
Add symlinks to replace SVN externals
Cast to avoid compile error
Separate package-level and project-level make logic.  Create buildstamp data at package level.
Add sipXcallLib to main Makefile.am
Add files required by autotools
m4 macros: adapt for top level package layout
MpAudioUtils.cpp: add missing include statement
Various improvements: disable sipviewer by default, search for librt, modernise autotools syntax, add m4 and build-aux directories, removing custom paths for PCRE and OpenSSL
Using headers from related projects in source tree.  Simplify PCRE and OpenSSL inclusion.