+dnl C functions which may be missing on older systems.
+AC_CHECK_FUNCS([inotify_init1 clock_gettime])
+
+dnl Check for required packages using pkg-config.
+PKG_CHECK_MODULES([HOSTINFOD],[apr-1 >= 1.3 libvirt >= 0.2.1])
+
+dnl Check for Perl and POD.
+AC_CHECK_PROG([PERL],[perl],[perl],[no])
+AC_CHECK_PROG([POD2MAN],[pod2man],[pod2man],[no])
+test "x$POD2MAN" = "xno" &&
+ AC_MSG_ERROR([pod2man must be installed])
+AC_CHECK_PROG([POD2TEXT],[pod2text],[pod2text],[no])
+test "x$POD2TEXT" = "xno" &&
+ AC_MSG_ERROR([pod2text must be installed])
+