Remove build issues with MacOSX and latest XC32 compiler

* Changed VERSION define to use `git rev-list HEAD --count`
to avoid issue on MacOSX where the result from wc is indented
and causes an invalid build command.

* Added define `_SUPPRESS_PLIB_WARNING` to remove deprecated plib
warnings when using xc32 v1.32.

* Added procdefs.ld to the default project configuration to avoid linking failure.