AC_CHECK_FUNCS([gettimeofday isatty sigrelse getpwuid_r memalign posix_memalign if_nametoindex getenv putenv setenv ctime_r daemon fork lstat posix_fadvise posix_madvise uselocale])
AC_FUNC_ALLOCA
AC_CHECK_FUNCS(fcntl)
-AC_REPLACE_FUNCS([asprintf atof atoll getcwd gmtime_r lldiv localtime_r rewind strcasecmp strcasestr strdup strlcpy strncasecmp strndup strnlen strsep strtof strtoll vasprintf swab])
+AC_REPLACE_FUNCS([asprintf atof atoll getcwd getpid gmtime_r lldiv localtime_r rewind strcasecmp strcasestr strdup strlcpy strncasecmp strndup strnlen strsep strtof strtoll vasprintf swab])
AC_CHECK_FUNCS([stricmp strnicmp])
AC_CHECK_FUNCS(fdatasync,,
[AC_DEFINE(fdatasync, fsync, [Alias fdatasync() to fsync() if missing.])