Log message:
Split out the code that deals with checking whether the software is
built-in or not into a separate builtin.mk file.  The code to deal
checking for built-in software is much simpler to deal with in pkgsrc.

The buildlink3.mk file for a package will be of the usual format
regardless of the package, which makes it simpler for packagers to
update a package.

The builtin.mk file for a package must define a single yes/no variable
USE_BUILTIN.<pkg> that is used by bsd.buildlink3.mk to decide whether
to use the built-in software or to use the pkgsrc software.

Log message:
Add BUILDLINK_DEPENDS.<pkg> for dependencies in a section that is invoked
only if we're not using the built-in versions of the package.

Log message:
Move the settings, which force the use of builtin versions of dependencies
if the builtin version of the package is being used, into a global
location so that they're always executed.

Log message:
If we're using the built-in version of the software, then we must also
be using built-in versions of any other software pulled in via
buildlink3.mk files.

Log message:
Reorder some lines so that BUILDLINK_USE_BUILTIN.<pkg> set in the
environment overrides all other settings.

Log message:
fontconfig had a really weird version numbering system.  Version 2.0 is
practically verbatim with the "1.0.1" release that's in XFree86 4.3.x.
There have in fact been only function additions to the fontconfig API
since 2.0, so fontconfig has never actually had a bump in the shared
library major.  Therefore, allow "fontconfig>=1.0.1" as the base
requirement.

Log message:
When using the native version of this library, symlink the .pc file into
the buildlink directory so that pkg-config can find it.  Ok'ed by jlam@.

Log message:
Missing a "=" in the ">=".

Log message:
Don't include other buildlink3.mk files if we're just checking whether the
software is built-in.

Log message:
fontconfig is in the "fonts" category.