cgit build on riscv64 machine

[Bo YU]

Hi,
(very sorry if resend the mail, it seems that my email client has issue)
I am trying to build cgit on riscv64 arch. But it fails due to
test case failed:

```
not ok 1 - do not access $HOME:
#
#                       test_no_home_access ''
#
not ok 2 - do not access $HOME: foo
#
#                       test_no_home_access 'foo'
#
not ok 3 - do not access $HOME: foo/refs
#
#                       test_no_home_access 'foo/refs'
#
not ok 4 - do not access $HOME: foo/log
#
#                       test_no_home_access 'foo/log'
#
not ok 5 - do not access $HOME: foo/tree
#
#                       test_no_home_access 'foo/tree'
#
not ok 6 - do not access $HOME: foo/tree/file-1
#
#                       test_no_home_access 'foo/tree/file-1'
#
not ok 7 - do not access $HOME: foo/commit
#
#                       test_no_home_access 'foo/commit'
#
not ok 8 - do not access $HOME: foo/diff
#
#                       test_no_home_access 'foo/diff'
#
not ok 9 - do not access $HOME: foo/patch
#
#                       test_no_home_access 'foo/patch'
#
not ok 10 - do not access $HOME: foo/snapshot/master.tar.gz
#
#                       test_no_home_access 'foo/snapshot/master.tar.gz'
#
# failed 10 among 10 test(s)
1..10
make[1]: *** [Makefile:12: t0109-gitconfig.sh] Error 1
make: *** [Makefile:83: test] Error 2
```

I have real riscv64 hardware by hand so I can test it, so any help will
be appericated!

Bo