For each link given as http://, verify that the site is accessible over
https:// and, if so, switch to it. These domains were converted:
* llvm.org
* clang.llvm.org
* en.cppreference.com
* www.dxx-rebirth.com
* www.libsdl.org
* www.scons.org
Starting in gcc 4.7 "Windows mingw targets are using the -mms-bitfields
option by default." <http://gcc.gnu.org/gcc-4.7/changes.html>. This
causes __attribute__((packed)) not to be effective on structures that
are used to express the layout of on-disk data. In turn, that causes
piggy.c to mishandle texture loads, eventually resulting in an infinite
loop. Add a pragma pack to force the headers to pack tightly on
Windows.