This patch is taken from Debian, using Debian version 1.7.0-8.
A new patch will be needed when apr is updated.

# quick and dirty fix for FTBFS on mipsel
# There should be a proper configure check, see 
# https://bz.apache.org/bugzilla/show_bug.cgi?id=63566
Index: apr-1.7.0/include/arch/unix/apr_arch_atomic.h
===================================================================
--- apr-1.7.0.orig/include/arch/unix/apr_arch_atomic.h
+++ apr-1.7.0/include/arch/unix/apr_arch_atomic.h
@@ -26,6 +26,9 @@
 /* noop */
 #elif HAVE_ATOMIC_BUILTINS
 #   define USE_ATOMICS_BUILTINS
+#   if (__INTPTR_WIDTH__ == 32) && ( defined(__MIPSEL__) || defined(__powerpc__) ) || defined(__m68k__) || defined(__sh__)
+#       define NEED_ATOMICS_GENERIC64
+#   endif
 #elif defined(SOLARIS2) && SOLARIS2 >= 10
 #   define USE_ATOMICS_SOLARIS
 #   define NEED_ATOMICS_GENERIC64
Index: apr-1.7.0/atomic/unix/builtins64.c
===================================================================
--- apr-1.7.0.orig/atomic/unix/builtins64.c
+++ apr-1.7.0/atomic/unix/builtins64.c
@@ -16,7 +16,7 @@
 
 #include "apr_arch_atomic.h"
 
-#ifdef USE_ATOMICS_BUILTINS
+#if defined(USE_ATOMICS_BUILTINS) && ! defined(NEED_ATOMICS_GENERIC64)
 
 APR_DECLARE(apr_uint64_t) apr_atomic_read64(volatile apr_uint64_t *mem)
 {
Index: apr-1.7.0/atomic/unix/builtins.c
===================================================================
--- apr-1.7.0.orig/atomic/unix/builtins.c
+++ apr-1.7.0/atomic/unix/builtins.c
@@ -20,7 +20,11 @@
 
 APR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p)
 {
+#if defined (NEED_ATOMICS_GENERIC64)
+    return apr__atomic_generic64_init(p);
+#else
     return APR_SUCCESS;
+#endif
 }
 
 APR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem)
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</td></tr></table>
<div class='path'>path: <a href='/guix/log/?showmsg=1'>root</a>/<a href='/guix/log/etc?showmsg=1'>etc</a>/<a href='/guix/log/etc/snippets?showmsg=1'>snippets</a>/<a href='/guix/log/etc/snippets/tempel?showmsg=1'>tempel</a>/<a href='/guix/log/etc/snippets/tempel/scheme-mode?showmsg=1'>scheme-mode</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/etc/snippets/tempel/scheme-mode'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2024-09-21 11:05:36 -0500'>2024-09-21</span></td><td class='logsubject'><a href='/guix/commit/etc/snippets/tempel/scheme-mode?id=e602b799fb751ab74eb6fe6d395905a962785085'>.dir-locals.el: Add tempel snippets.</a></td><td>Nicolas Graves</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
Change-Id: Ic16f571f26fffee12e478e00c54be55e6eb90831
Signed-off-by: jgart &lt;jgart@dismail.de&gt;


</td></tr>
<tr class='logheader'><td><span title='2023-10-15 12:28:19 +0200'>2023-10-15</span></td><td class='logsubject'><a href='/guix/commit/etc/snippets/tempel/scheme-mode?id=ef026e68fe58ed3be216c76f7c5f008893ed3095'>etc: snippets: Do not match unintended quotes.</a></td><td>Liliana Marie Prikler</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* etc/snippets/tempel/scheme-mode (origin): Unquote ‘git-fetch’, ‘svn-fetch’,
‘hg-fetch’, ‘cvs-fetch’, and ‘bzr-fetch’.  Use ‘otherwise’ instead of ‘t’.


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