Move bzip2 and zlib buildlink3 out of the png PKG_OPTION check, they are
unconditional dependencies.
Move fuse support into a default-off option.

Fuse support being on breaks the build on mac, where our wrappers for
OSXFUSE seem not quite right, and fuse support doesn't work on NetBSD.
ok wiz@ (as MAINTAINER).
Add patch from upstream to avoid failures due to clang warnings.

Resolves failure to build on OS X 10.9.

ok wiz@ (as MAINTAINER).
Only build hcrypto on MirBSD if using the builtin OpenSSL. Fixes build
now that we have OpenSSL from pkgsrc.