You might also need to check for the existence of files. Before using
these macros, ask yourself whether a runtime test might not be a better
solution. Be aware that, like most Autoconf macros, they test a feature
of the host machine, and therefore, they die when cross-compiling.
— Macro: AC_CHECK_FILE
(file, [action-if-found], [action-if-not-found]
Check whether file file exists on the native system. If it is
found, execute action-if-found, otherwise do
action-if-not-found, if given.
— Macro: AC_CHECK_FILES
(files, [action-if-found], [action-if-not-found]
AC_CHECK_FILE once for each file listed in files.
Additionally, defines ‘HAVE_file’ (see Standard Symbols)
for each file found.