Minimally patch libtheora's ancient config.guess to support mips64.

--- libtheora/config.guess.orig	2009-02-23 22:50:50.000000000 -0500
+++ libtheora/config.guess	2013-10-31 23:49:48.155999944 -0400
@@ -798,25 +798,24 @@
     m68*:Linux:*:*)
 	echo ${UNAME_MACHINE}-unknown-linux-gnu
 	exit 0 ;;
-    mips:Linux:*:*)
+    mips:Linux:*:* | mips64:Linux:*:*)
 	eval $set_cc_for_build
 	sed 's/^	//' << EOF >$dummy.c
 	#undef CPU
-	#undef mips
-	#undef mipsel
+	#undef ${UNAME_MACHINE}
+	#undef ${UNAME_MACHINE}el
 	#if defined(__MIPSEL__) || defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL)
-	CPU=mipsel
+	CPU=${UNAME_MACHINE}el
 	#else
 	#if defined(__MIPSEB__) || defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB)
-	CPU=mips
+	CPU=${UNAME_MACHINE}
 	#else
 	CPU=
 	#endif
 	#endif
 EOF
-	eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep ^CPU=`
-	rm -f $dummy.c && rmdir $tmpdir
-	test x"${CPU}" != x && echo "${CPU}-pc-linux-gnu" && exit 0
+	eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep '^CPU'`
+	test x"${CPU}" != x && { echo "${CPU}-unknown-linux-gnu"; exit 0; }
 	;;
     ppc:Linux:*:*)
 	echo powerpc-unknown-linux-gnu
tive' href='/guix/log/etc/openrc'>log</a><a href='/guix/tree/etc/openrc?id=09df4ef4f667ae1322ea517111889adcdead5fda'>tree</a><a href='/guix/commit/etc/openrc?id=09df4ef4f667ae1322ea517111889adcdead5fda'>commit</a><a href='/guix/diff/etc/openrc?id=09df4ef4f667ae1322ea517111889adcdead5fda'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/etc/openrc'>
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<tr><td><span title='2021-07-07 23:54:20 -0400'>2021-07-07</span></td><td><a href='/guix/commit/etc/openrc?id=4cbe0127a668cbcc64087c5d311308b59d39b104'>guix-install.sh: Prompt for configuring substitutes discovery.</a><span class='msg-avail'>...<span class='msg-tooltip'>Also ensure prompt_yes_no always print the message with a trailing space,
which is more pleasing to the eye.

* etc/guix-daemon.conf.in &lt;--discover=no&gt;: New guix-daemon option.
* etc/guix-daemon.service.in: Likewise.
* etc/init.d/guix-daemon.in: Likewise.
* etc/openrc/guix-daemon.in: Likewise.
* etc/guix-install.sh (configure_substitute_discovery): New procedure.
(sys_enable_guix_daemon): Ask the user whether automatic substitute discovery
should be enabled.  Set the '--discover' argument accordingly.
(prompt_yes_no): Add a trailing space to the message.
(sys_authorize_build_farms): Remove trailing space from the message argument.
* NEWS (Distribution): Add news.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2020-09-17 14:10:42 +0200'>2020-09-17</span></td><td><a href='/guix/commit/etc/openrc?id=cabac732deffafc796537658a6c33c6c4aec821e'>guix-install.sh: Support OpenRC.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-install.sh (chk_init_sys): Detect OpenRC.
(sys_enable_guix_daemon): Install &amp; enable the Guix daemon on such
systems.
* etc/openrc/guix-daemon.in: New file.
* nix/local.mk: Add a rule for it.
(openrcservicedir, nodist_openrcservice_DATA): New variables.
(CLEANFILES, EXTRA_DIST): Add them.
* .gitignore: Ignore etc/openrc/guix-daemon.

Signed-off-by: Tobias Geerinckx-Rice &lt;me@tobias.gr&gt;
</span></span></td><td>Morgan Smith</td></tr>