Merge pull request #291 from Alexpux/develop

Merge mingw-w64-builds branch into develop
Update TODO.
Merge pull request #292 from Alexpux/develop

Release 4.0.0 version of mingw-w64-build scripts.
Add ability to build full static GCC - fix issue #256.
Merge pull request #294 from Alexpux/develop

Add ability to build full static GCC - fix issue #256.
Fix gcc-post script for static GCC build.
Merge pull request #295 from Alexpux/develop

Fix gcc-post script for static GCC build.
Fix migw-w64-runtime-post and tests scripts for GCC static build.
Merge pull request #296 from Alexpux/develop

Fix migw-w64-runtime-post and tests scripts for GCC static build.
Build shared and static GCC in separate folders. Also create separate archives.
Merge pull request #297 from Alexpux/develop

Build shared and static GCC in separate folders. Also create separate archives
Fix readonly variable definition.
Fix variables creation order.
Build zlib shared and static in separate folders
Merge pull request #298 from Alexpux/develop

Fix GCC static configuration variables.
Add new PKG_LNDIR variable that tell configure function to try ln source directory to build directory. This need for some packages like  zlib that build inside source tree.
Fix previous commit
Merge pull request #299 from Alexpux/develop

Add possibility to build packages that need to be build inside sources (like zlib)
We don't need to have extra directory for building inside source tree.
Fix marker name.