Build/Install failing for gmp-6.2.0 on Powerbook G4

[Code Dragon]

I'm trying to get FreeBSD running on a Powerbook G4 (12 inch  6,4
1.3Ghz).  When building some ports I ran into a pair of issues with
gmp-6.2.0:

First: I run into an issue where it tries to build for an invalid architecture:
---------------------------------------------------------------------------------------------------------
checking build system type... invalid configuration
'powerpc7447-unknown-freebsd12.1': machine 'powerpc7447-unknown' not
recognized

configure: error: /bin/sh ./config.sub powerpc7447-unknown-freebsd12.1
failed
---------------------------------------------------------------------------------------------------------

I got around this using this workaround:
# make configure CONFIGURE_ARGS=--build=powerpc

The second issue is that once the build is complete and I try to install I get:
----------------------------------------------------------------------------------------------------------
===> Installing for gmp-6.2.0
===> Checking if gmp is already installed
===>  Registering installation for gmp-6.2.0
pkg-static: Unable to access file
/usr/ports/math/gmp/work/stage/usr/local/include/gmpxx.h:No such file
or directory
pkg-static: Unable to access file
/usr/ports/math/gmp/work/stage/usr/local/lib/libgmp.so:No such file or
directory
pkg-static: Unable to access file
/usr/ports/math/gmp/work/stage/usr/local/lib/libgmp.so.10:No such file
or directory
pkg-static: Unable to access file
/usr/ports/math/gmp/work/stage/usr/local/lib/libgmp.so.10.4.0:No such
file or directory
pkg-static: Unable to access file
/usr/ports/math/gmp/work/stage/usr/local/lib/libgmpxx.so:No such file
or directory
pkg-static: Unable to access file
/usr/ports/math/gmp/work/stage/usr/local/lib/libgmpxx.so.4:No such
file or directory
pkg-static: Unable to access file
/usr/ports/math/gmp/work/stage/usr/local/lib/libgmpss.so.4.6.0:No such
file or directory
pkg-static: Unable to access file
/usr/ports/math/gmp/work/stage/usr/local/libdata/pkgconfig/gmpxx.pc:No
such file or directory
*** Error code 74
...
--------------------------------------------------------------------------------------------------------------

Any suggestions of my next steps?

--kehvarl