support blank arguments for Unix.open_process and friends
add manifest for 32-bit builds
Merge pull request #2 from vprevosto/new-packages

add packages for coq and alt-ergo
Merge pull request #1 from vprevosto/open-process-blank-args

support blank arguments for Unix.open_process and friends
coq / alt-ergo relocatability
cygwin64 fixes / package updates