makepkg: provide environmental variable to disable PKGBUILD linting
On Windows based systems (e.g. msys), running PKGBUILD linting is very slow due to time taken spawning bash subshells. Additionally, some packages have extreme amounts of (usually procedurally generated) splitting, which also causes linting to be extremely slow. Provide an enviromental variable to disable PKGBUILD linting.
Signed-off-by: Allan McRae allan@archlinux.org