Fixed ./autogen.sh warnings due to AC_USE_SYSTEM_EXTENSIONS.
Ensured that ./configure checks for the C99 <stdbool.h> header.

See: http://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Particular-Headers.html
Updated the TODO list with upstream build toolchain enhancements.
Ensured that ./configure checks for the C <assert.h> header.

See: http://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Particular-Headers.html
Documented all library-specific ./configure options.
Added information to the FAQ regarding successful build targets.
Added some compatibility notes to the Mac OS X installation section.
Removed the specific mentions of C11 in favor of generic C.
Added some miscellaneous material and placeholders to the manual.
Added source repository installation instructions for all platforms.