component/git: backport a fix for parrallel make
fix this error:
  t/unit-tests/clar/clar.c:209:10: fatal error: clar.suite: No such file or directory
  209 | #include "clar.suite"
        |          ^~~~~~~~~~~~
  compilation terminated.
  make: *** [Makefile:2795: t/unit-tests/clar/clar.o] Error 1
  git: Command 'set -e;make ' returned non-zero exit status 2.
  git: Compilation error. The package is left as is at /srv/slapgrid/slappart47/t/drw/shared/git/832728c0d7e76c5e768f4e3b2767d29d/.build/git-2.47.1 where you can inspect what went wrong.
  A shell script slapos.recipe.build.env.sh has been generated. You can source it in your shell to reproduce build environment.
  While:
  Installing git.
  Error: System error