This fixes

../../../../gcc-7.4.0/libstdc++-v3/libsupc++/new_opa.cc: In function ‘void* __gnu_cxx::aligned_alloc(std::size_t, std::size_t)’:
../../../../gcc-7.4.0/libstdc++-v3/libsupc++/new_opa.cc:78:10: error: ‘memalign’ was not declared in this scope
   return memalign (al, sz);
          ^~~~~~~~
../../../../gcc-7.4.0/libstdc++-v3/libsupc++/new_opa.cc:78:10: note: suggested alternative: ‘max_align_t’
   return memalign (al, sz);
          ^~~~~~~~
          max_align_t

diff --git a/libstdc++-v3/libsupc++/new_opa.cc b/libstdc++-v3/libsupc++/new_opa.cc
index 94e79cadb0e..084900e0daf 100644
--- a/libstdc++-v3/libsupc++/new_opa.cc
+++ b/libstdc++-v3/libsupc++/new_opa.cc
@@ -39,6 +39,8 @@ extern "C" void *memalign(std::size_t boundary, std::size_t size);
 # endif
 #endif
 
+#define memalign _aligned_malloc
+
 using std::new_handler;
 using std::bad_alloc;
 
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<tr><td><span title='2021-01-21 11:22:08 +0100'>2021-01-21</span></td><td><a href='/guix/commit/tests/swh.scm?id=5225732b9b54ffa92b9d199246b87dae666a3f77'>swh: Test proper handling of null visit snapshot URL.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/swh.scm (%origin): Change "visits_url" to "origin_visits_url".
(%visits): New variable.
("origin-visit, no snapshots"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-12-21 17:47:35 +0100'>2020-12-21</span></td><td><a href='/guix/commit/tests/swh.scm?id=9608f4003dedd8dfe99327c15668ca1a43ebd93b'>tests: Fix malformed JSON.</a><span class='msg-avail'>...<span class='msg-tooltip'>Guile-JSON 4.3.2 would parse in spite of these typos, but 4.4.1 is
stricter.

* tests/swh.scm (%directory-entries): Add missing comma.
* tests/cve-sample.json: Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>