diff -up asymptote-2.41/configure.ac.libtirpc asymptote-2.41/configure.ac
--- asymptote-2.41/configure.ac.libtirpc 2018-03-23 15:34:45.062744013 -0400
+++ asymptote-2.41/configure.ac 2018-03-23 15:36:42.444110780 -0400
@@ -268,6 +268,17 @@ AC_HEADER_SYS_WAIT
AC_CHECK_HEADERS([fenv.h stddef.h libintl.h])
AC_CHECK_HEADERS(fpu_control.h)
+PKG_PROG_PKG_CONFIG([0.9.0])
+AS_IF(
+ [test "$enable_tirpc" != "no"],
+ [PKG_CHECK_MODULES([TIRPC], [libtirpc >= 0.2.4],
+ [LIBS="${LIBS} ${TIRPC_LIBS}"
+ CPPFLAGS="${CPPFLAGS} ${TIRPC_CFLAGS}"
+ AC_DEFINE([HAVE_LIBTIRPC], [1],
+ [Define to 1 if you have and wish to use libtirpc.])],
+ [AS_IF([test "$enable_tirpc" != "no"], [AC_MSG_ERROR([libtirpc not found.])],
+ [LIBTIRPC=""])])])
+
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include "xstream.h"])],
[AC_SEARCH_LIBS([xdrstdio_create],[nsl rpc])
AC_DEFINE(HAVE_RPC_RPC_H, 1,