+dnl --------------------- Check if realpath() takes NULL
+AC_CACHE_CHECK([if the realpath function allows a NULL argument],
+ neta_cv_REALPATH_TAKES_NULL, [
+ AC_TRY_RUN([
+ #include <stdio.h>
+ #include <limits.h>
+ #include <signal.h>
+
+ void exit_on_core(int ignored) {
+ exit(1);
+ }
+
+ main() {
+ char *newpath;
+ signal(SIGSEGV, exit_on_core);
+ newpath = realpath("/tmp", NULL);
+ exit((newpath != NULL) ? 0 : 1);
+ }],
+ neta_cv_REALPATH_TAKES_NULL=yes,
+ neta_cv_REALPATH_TAKES_NULL=no,
+ neta_cv_REALPATH_TAKES_NULL=cross
+ )
+ ]
+)
+
+if test x"$neta_cv_REALPATH_TAKES_NULL" = x"yes"; then
+ AC_DEFINE(REALPATH_TAKES_NULL,1,[Whether the realpath function allows NULL])
+fi
+