Unix port doesn't build if the variant is a symbolic link

Due to project organisation reasons I have my own MicroPython custom Unix port variant outside the MicroPython source tree. With MicroPython 1.21.0, when putting a symbolic link from my variant directory to the port's variants/ directory (so a new directory shows up there), building fails. I guess that one or more python scripts in the build either resolve symbolic links (or they don't, no idea)?

The errors are as follows (Arch Linux, clean build):

mkdir -p build-TEST_RUNNER/genhdr
mkdir -p build-TEST_RUNNER/build-TEST_RUNNER/
mkdir -p build-TEST_RUNNER/extmod/
mkdir -p build-TEST_RUNNER/lib/berkeley-db-1.xx/btree/
mkdir -p build-TEST_RUNNER/lib/berkeley-db-1.xx/mpool/
mkdir -p build-TEST_RUNNER/lib/littlefs/
mkdir -p build-TEST_RUNNER/lib/mbedtls/library/
mkdir -p build-TEST_RUNNER/lib/mbedtls_errors/
mkdir -p build-TEST_RUNNER/lib/oofatfs/
mkdir -p build-TEST_RUNNER/py/
mkdir -p build-TEST_RUNNER/shared/libc/
mkdir -p build-TEST_RUNNER/shared/readline/
mkdir -p build-TEST_RUNNER/shared/runtime/
mkdir -p build-TEST_RUNNER/shared/timeutils/
GEN build-TEST_RUNNER/genhdr/mpversion.h
GEN build-TEST_RUNNER/genhdr/qstr.i.last
In file included from ./mpconfigport.h:36,
                 from ../../py/mpconfig.h:75,
                 from ../../py/mpstate.h:31,
                 from ../../py/mpstate.c:27:
variants/TEST_RUNNER/mpconfigvariant.h:3:10: fatal error: ../mpconfigvariant_common.h: No such file or directory
    3 | #include "../mpconfigvariant_common.h"
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
[A few more of these]
Traceback (most recent call last):
  File "<...>/micropython/ports/unix/../../py/makeqstrdefs.py", line 211, in <module>
    preprocess()
  File "<...>/micropython/ports/unix/../../py/makeqstrdefs.py", line 76, in preprocess
    for output in p.imap(pp(flags), chunks):
  File "/usr/lib/python3.11/multiprocessing/pool.py", line 873, in next
    raise value
  File "/usr/lib/python3.11/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
                    ^^^^^^^^^^^^^^^^^^^
  File "<...>/micropython/ports/unix/../../py/makeqstrdefs.py", line 60, in run
    return subprocess.check_output(args.pp + flags + files)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/subprocess.py", line 466, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/subprocess.py", line 571, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['gcc', '-E', '-DMICROPY_VFS_FAT=1', '-DMICROPY_VFS_LFS1=1', '-DMICROPY_VFS_LFS2=1', '-DMICROPY_PY_SSL=1', '-DMBEDTLS_CONFIG_FILE="mbedtls/mbedtls_config.h"', '-DMICROPY_SSL_MBEDTLS=1', '-I../../lib/mbedtls/include', '-DMICROPY_PY_BTREE=1', '-DFFCONF_H="lib/oofatfs/ffconf.h"', '-DLFS1_NO_MALLOC', '-DLFS1_NO_DEBUG', '-DLFS1_NO_WARN', '-DLFS1_NO_ERROR', '-DLFS1_NO_ASSERT', '-DLFS2_NO_MALLOC', '-DLFS2_NO_DEBUG', '-DLFS2_NO_WARN', '-DLFS2_NO_ERROR', '-DLFS2_NO_ASSERT', '-I../../lib/berkeley-db-1.xx/PORT/include', '-I.', '-I../..', '-Ibuild-TEST_RUNNER', '-I../../shared/readline', '-Wall', '-Werror', '-Wextra', '-Wno-unused-parameter', '-Wpointer-arith', '-Wdouble-promotion', '-Wfloat-conversion', '-std=gnu99', '-DUNIX', '-Os', '-DNDEBUG', '-fdata-sections', '-ffunction-sections', '-Ivariants/TEST_RUNNER', '-g', '-U', '_FORTIFY_SOURCE', '-DMICROPY_USE_READLINE=1', '-DMICROPY_PY_TERMIOS=1', '-DMICROPY_PY_SOCKET=1', '-DMICROPY_PY_THREAD=1', '-DMICROPY_PY_THREAD_GIL=0', '-DMICROPY_PY_FFI=1', '-DMPZ_DIG_SIZE=16', '-DMICROPY_ROM_TEXT_COMPRESSION=1', '-DNO_QSTR', '../../py/mpstate.c', '../../py/malloc.c', '../../py/gc.c', '../../py/pystack.c', '../../py/qstr.c', '../../py/vstr.c', '../../py/mpprint.c', '../../py/unicode.c', '../../py/mpz.c', '../../py/reader.c', '../../py/lexer.c', '../../py/parse.c', '../../py/scope.c', '../../py/compile.c', '../../py/emitcommon.c', '../../py/emitbc.c', '../../py/asmbase.c', '../../py/asmx64.c', '../../py/emitnx64.c', '../../py/asmx86.c', '../../py/emitnx86.c', '../../py/asmthumb.c', '../../py/emitnthumb.c']' returned non-zero exit status 1.
In file included from ./mpconfigport.h:36,
                 from ../../py/mpconfig.h:75,
                 from ../../py/obj.h:31,
                 from ../../py/builtin.h:29,
                 from ../../py/builtinhelp.c:30:
variants/TEST_RUNNER/mpconfigvariant.h:3:10: fatal error: ../mpconfigvariant_common.h: No such file or directory
    3 | #include "../mpconfigvariant_common.h"
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
make: *** [../../py/mkrules.mk:111: build-TEST_RUNNER/genhdr/qstr.i.last] Error 1
make: *** Deleting file 'build-TEST_RUNNER/genhdr/qstr.i.last'

A quick way to reproduce the issue is as such (it also happens on Git HEAD):

cd micropython/ports/unix
mv variants/standard ../..
cd variants
ln -s ../../../standard standard
cd ..
make