updated INSTALL.markdown instructions
Ported some m4 code out of old projects.
Lots of build system refactoring.
Bundled the autoconf archive license for two of the m4 macros.
Resolve issues raised by `autoscan`
Detect posix_fadvise and a few other functions. Detect how to inline on a given platform.
Added c_sync
Expose prefetch and sync to Haskell.
Set up a postHaddock hook to copy image files into the haddock folder.
adding clearer explanation to the prefetch haskell operation

Signed-off-by: Carter Tazio Schonwald <carter.schonwald@gmail.com>