[SSSD] [sssd PR#5289][opened] build: Don't use AC_CHECK_FILE when building manpages

[jonte]

URL: https://github.com/SSSD/sssd/pull/5289
Author: jonte
 Title: #5289: build: Don't use AC_CHECK_FILE when building manpages
Action: opened

PR body:
"""
AC_CHECK_FILE does not support cross-compilation, and will only check
the host rootfs. Replace AC_CHECK_FILE with a 'test -f <FILE>' instead,
to allow building manpages when cross-compiling.

Signed-off-by: Jonatan Pålsson 
"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/5289/head:pr5289
git checkout pr5289