Build with libtirpc on all architectures because glibc no longer provides
SunRPC support.

diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -23635,10 +23635,13 @@
   *-pc-cygwin*)
     LIBS="$LIBS -ltirpc"
     CPPFLAGS="$CPPFLAGS -I/usr/include/tirpc"  ;;
+  *-linux-gnu)
+    LIBS="$LIBS -ltirpc"
+    CPPFLAGS="$CPPFLAGS"  ;;
   *) ;;
 esac
 
-if test "X$BUILD_XDR" != "Xyes"; then
+if test "X$BUILD_XDR" = "Xyes"; then
     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -23693,9 +23696,9 @@
   ## but we need to make sure that it is present on the system. Do that here,
   ## The SunRPC of the glibc has been replaced by a TI-RPC (Transport Independent RPC) library for IPv6 support
   case "$host" in
-    *-pc-cygwin*)
+    *)
       HAVE_RPC="yes"
-      ac_fn_c_check_header_mongrel "$LINENO" "rpc.h" "ac_cv_header_rpc_h" "$ac_includes_default"
+      ac_fn_c_check_header_mongrel "$LINENO" "rpc/rpc.h" "ac_cv_header_rpc_h" "$ac_includes_default"
 if test "x$ac_cv_header_rpc_h" = xyes; then :
   :
 else
 href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=06b1d6954aa6cf7123745136df41bc949b591f1c'>refs</a><a class='active' href='/guix/log/gnu/packages/simulation.scm'>log</a><a href='/guix/tree/gnu/packages/simulation.scm?id=06b1d6954aa6cf7123745136df41bc949b591f1c'>tree</a><a href='/guix/commit/gnu/packages/simulation.scm?id=06b1d6954aa6cf7123745136df41bc949b591f1c'>commit</a><a href='/guix/diff/gnu/packages/simulation.scm?id=06b1d6954aa6cf7123745136df41bc949b591f1c'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/simulation.scm'>
<input type='hidden' name='id' value='06b1d6954aa6cf7123745136df41bc949b591f1c'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=06b1d6954aa6cf7123745136df41bc949b591f1c'>root</a>/<a href='/guix/log/gnu?id=06b1d6954aa6cf7123745136df41bc949b591f1c'>gnu</a>/<a href='/guix/log/gnu/packages?id=06b1d6954aa6cf7123745136df41bc949b591f1c'>packages</a>/<a href='/guix/log/gnu/packages/simulation.scm?id=06b1d6954aa6cf7123745136df41bc949b591f1c'>simulation.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/simulation.scm?id=06b1d6954aa6cf7123745136df41bc949b591f1c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2017-12-01 11:28:48 +0100'>2017-12-01</span></td><td><a href='/guix/commit/gnu/packages/simulation.scm?id=f1de0e37d579dc7834be0c9e80654e9f2067c3ed'>gnu: openfoam: Clean up to reduce closure.</a><span class='msg-avail'>...</span></td><td>Dave Love</td></tr>
<tr><td><span title='2017-09-20 23:02:28 +0200'>2017-09-20</span></td><td><a href='/guix/commit/gnu/packages/simulation.scm?id=a836e9f509b2b924bd47967fcb71723af3fac6fd'>gnu: openfoam: Fix typo in Note.</a><span class='msg-avail'>...</span></td><td>Paul Garlick</td></tr>
<tr><td><span title='2017-09-17 10:14:17 +0300'>2017-09-17</span></td><td><a href='/guix/commit/gnu/packages/simulation.scm?id=b6598237f224f15f8f24de21acb38178da0e0540'>gnu: openfoam: Fix typo.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2017-09-15 18:31:53 +0200'>2017-09-15</span></td><td><a href='/guix/commit/gnu/packages/simulation.scm?id=8f21aa22bf4b731ed0e5631c371846028e5cec0d'>gnu: Add openfoam.</a><span class='msg-avail'>...</span></td><td>Paul Garlick</td></tr>