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;
 
'switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=1be7f437568ca6a238e2172a37720f5529021d49'>refs</a><a class='active' href='/guix/log/tests/minetest.scm'>log</a><a href='/guix/tree/tests/minetest.scm?id=1be7f437568ca6a238e2172a37720f5529021d49'>tree</a><a href='/guix/commit/tests/minetest.scm?id=1be7f437568ca6a238e2172a37720f5529021d49'>commit</a><a href='/guix/diff/tests/minetest.scm?id=1be7f437568ca6a238e2172a37720f5529021d49'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/minetest.scm'>
<input type='hidden' name='id' value='1be7f437568ca6a238e2172a37720f5529021d49'/><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=1be7f437568ca6a238e2172a37720f5529021d49'>root</a>/<a href='/guix/log/tests?id=1be7f437568ca6a238e2172a37720f5529021d49'>tests</a>/<a href='/guix/log/tests/minetest.scm?id=1be7f437568ca6a238e2172a37720f5529021d49'>minetest.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/tests/minetest.scm?id=1be7f437568ca6a238e2172a37720f5529021d49&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-01-06 16:27:30 +0100'>2022-01-06</span></td><td><a href='/guix/commit/tests/minetest.scm?id=9f526f5dad5f4af69d158c50369e182305147f3b'>upstream: Support updating and fetching 'git-fetch' origins.</a><span class='msg-avail'>...</span></td><td>Sarah Morgensen</td></tr>
<tr><td><span title='2021-10-02 17:16:43 +0200'>2021-10-02</span></td><td><a href='/guix/commit/tests/minetest.scm?id=085a8a0cdfef7c414c92dcf2b0ea9aa970888a62'>import/minetest: Define an updater for mods on ContentDB.</a><span class='msg-avail'>...</span></td><td>Maxime Devos</td></tr>
<tr><td><span title='2021-09-28 22:00:47 +0200'>2021-09-28</span></td><td><a href='/guix/commit/tests/minetest.scm?id=2f5368d678aad334149b280e9dab90ec1635104b'>import: minetest: Fix typos.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2021-09-18 19:43:00 +0200'>2021-09-18</span></td><td><a href='/guix/commit/tests/minetest.scm?id=808f9ffbd3106da4c92d2367b118b98196c9e81e'>import: minetest: Strip "v" prefixes from the version number.</a><span class='msg-avail'>...</span></td><td>Maxime Devos</td></tr>
<tr><td><span title='2021-09-18 19:42:54 +0200'>2021-09-18</span></td><td><a href='/guix/commit/tests/minetest.scm?id=8480a2a5bb360b432877dd33dca80a61c5a698eb'>import: minetest: Delete duplicate dependencies.</a><span class='msg-avail'>...</span></td><td>Maxime Devos</td></tr>
<tr><td><span title='2021-09-18 19:41:15 +0200'>2021-09-18</span></td><td><a href='/guix/commit/tests/minetest.scm?id=8d4c0e3104fdee7d2548077f9c338008b3595853'>tests/minetest: Fix 'test-package*' indenting.</a><span class='msg-avail'>...</span></td><td>Maxime Devos</td></tr>
<tr><td><span title='2021-08-20 12:41:54 +0200'>2021-08-20</span></td><td><a href='/guix/commit/tests/minetest.scm?id=467e874a86dc3dd83fe10e5610823c011de6565a'>guix: Add ContentDB importer.</a><span class='msg-avail'>...</span></td><td>Maxime Devos</td></tr>