[AC_REQUIRE([AC_TYPE_UID_T])dnl
test -z "$ac_cv_header_unistd_h" \
&& AC_CHECK_HEADERS(unistd.h)
AC_CACHE_CHECK([for working chown], jm_cv_func_working_chown,
[AC_TRY_RUN([
# include <sys/types.h>
[AC_REQUIRE([AC_TYPE_UID_T])dnl
test -z "$ac_cv_header_unistd_h" \
&& AC_CHECK_HEADERS(unistd.h)
AC_CACHE_CHECK([for working chown], jm_cv_func_working_chown,
[AC_TRY_RUN([
# include <sys/types.h>