Changed attr/xattr.h to sys/xattr.h
Fixed #includes for xerces submodules
Added missing <cstdlib>
Updated Xerces from 2.7.0 (deprecated for security vulnerabilities) to 2.8.0
Fixes to CPPFLAGS to fix compilation errors
Fixed detection for POPT and LIBFUSELAGE
Added generated autoconf, automake, aclocal files and binaries to .gitignore