gcc12-libcxx patch phase fails on High Sierra

[blair (Blair Zajac)]

# uname -a
Darwin foobar.local 17.7.0 Darwin Kernel Version 17.7.0: Fri Oct 30 13:34:27 PDT 2020; root:xnu-4570.71.82.8~1/RELEASE_X86_64 x86_64 i386 Darwin
# port -v clean gcc12-libcxx
--->  Cleaning gcc12-libcxx
--->  Removing work directory for gcc12-libcxx
# ls /opt/local/var/macports/build/
# port -v outdated
The following installed ports are outdated:
gcc12                          12.2.0_1 < 12.2.0_2       
# port -v upgrade --enforce-variants outdated
--->  Computing dependencies for gcc12-libcxx.
--->  Fetching distfiles for gcc12-libcxx
--->  Verifying checksums for gcc12-libcxx
--->  Extracting gcc12-libcxx
--->  Patching Makefile.in: s|^do-compare =|do-compare = /usr/bin/true|g
Error: reinplace: couldn't read file "/opt/local/var/macports/build/_Users_blair_Code_MacPorts_macports-ports.git_lang_gcc12/gcc12-libcxx/work/gcc-12.2.0/Makefile.in": no such file or directory
Error: Failed to patch gcc12-libcxx: reinplace sed(1) failed
Error: See /opt/local/var/macports/logs/_Users_blair_Code_MacPorts_macports-ports.git_lang_gcc12/gcc12-libcxx/main.log for details.
Error: Problem while installing gcc12-libcxx
Error: Follow https://guide.macports.org/#project.tickets if you believe there
is a bug.
Command exited with non-zero status 1
2.29user 1.22system 0:03.70elapsed 94%CPU (0avgtext+0avgdata 49860maxresident)k
0inputs+0outputs (2major+49672minor)pagefaults 0swaps

[jmroot (Joshua Root)]

Different gcc port, but this is the same issue as #66277.

[Chris Jones <jonesc@…>]

In 7e8ac0ad0bdc1e00efef634e37968f32ab4b9480/macports-ports (master):

gccN-libcxx: Disable post-patch phase

Closes: #66282
Closes: #66277