Makefile: add target loop, serialise targets, and update settings file
add mingw-w64 runtime and pthreads implementation, update related toolchain files
Makefile: not all packages have urls (i.e. pthreads) so remove check
various packages: enable/disable mingw-w64 builds
packages libgnurx lensfun: enable mingw-w64 build
various packages: enable/modify mingw-w64 build
various packages: enable/modify mingw-w64 build
package qtbase: disable c++11 for i686-w64-mingw32

see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56038