Are there ways of bypassing libffi build?

[Paul Ackersviller <pda%sdf.org@localhost>]

The pkgsrc build of devel/libffi is badly broken on ia64-hp-hpux11.31,
but my question is easier than worrying how to fix that just yet.

Since upstream the build is trouble-free here, at least with gcc and
gmake, is there a way I can yell pkgsrc to use one I already have for
dependencies rather than building its own?

Alternatively, would ignoring pkgsrc patches be as simple as just
removing the patch files?