Provide a 'mach_print' symbol in libc.

--- a/sysdeps/mach/hurd/i386/libc.abilist	2020-04-01 19:22:44.710088821 +0200
+++ b/sysdeps/mach/hurd/i386/libc.abilist	2020-04-01 19:22:52.062051161 +0200
@@ -338,6 +338,7 @@
 GLIBC_2.2.6 __mach_port_allocate F
 GLIBC_2.2.6 __mach_port_deallocate F
 GLIBC_2.2.6 __mach_port_insert_right F
+GLIBC_2.21 __mach_print F
 GLIBC_2.2.6 __mach_reply_port F
 GLIBC_2.2.6 __mach_task_self_ D 0x4
 GLIBC_2.2.6 __mach_thread_self F

--- a/mach/Versions
+++ b/mach/Versions
@@ -56,6 +56,7 @@
   }
   GLIBC_2.21 {
     __mach_host_self_;
+    mach_print;
   }
 
   HURD_CTHREADS_0.3 {
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<tr><td><span title='2023-07-23 02:00:00 +0200'>2023-07-23</span></td><td><a href='/guix/commit/gnu/packages/patches/curlftpfs-fix-error-closing-file.patch?id=8244aea1829eec8aa68289d9832e3b77a26fbed9'>gnu: curlftpfs: Add patches to fix bugs.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/file-systems.scm (curlftpfs)[source]: Add patches.
* gnu/packages/patches/curlftpfs-fix-error-closing-file.patch,
gnu/packages/patches/curlftpfs-fix-file-names.patch,
gnu/packages/patches/curlftpfs-fix-memory-leak.patch,
gnu/packages/patches/curlftpfs-fix-no_verify_hostname.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>