Add pkgtool support

Update CGO preprocessor directives to use pkg-tool rather than
specifying the paths for local directories or the absolute path hacks.
Update header files with angle brackets instead of double quotes to use
system headers rather than local ones.
add cflag -std=gnu99
Merge branch 'pkgtool' of github.com:prevoty/hammer into pkgtool

Conflicts:
	action.c
	action.go
	hparseresult.go
	parse.go
	parsers.go