Fix esan compilation against glibc 2.26:

  /tmp/guix-build-clang-runtime-3.9.1.drv-0/compiler-rt-3.9.1.src/lib/esan/esan_sideline_linux.cpp: In static member function ‘static int __esan::SidelineThread::runSideline(void*)’:
  /tmp/guix-build-clang-runtime-3.9.1.drv-0/compiler-rt-3.9.1.src/lib/esan/esan_sideline_linux.cpp:73:22: error: aggregate ‘__esan::SidelineThread::runSideline(void*)::sigaltstack SigAltStack’ has incomplete type and cannot be defined

Patch from <https://github.com/google/sanitizers/issues/822>.

index d04f5909d..bc272dfe4 100644
--- a/lib/esan/esan_sideline_linux.cpp
+++ b/lib/esan/esan_sideline_linux.cpp
@@ -70,7 +70,7 @@ int SidelineThread::runSideline(void *Arg) {
 
   // Set up a signal handler on an alternate stack for safety.
   InternalScopedBuffer<char> StackMap(SigAltStackSize);
-  struct sigaltstack SigAltStack;
+  stack_t SigAltStack;
   SigAltStack.ss_sp = StackMap.data();
   SigAltStack.ss_size = SigAltStackSize;
   SigAltStack.ss_flags = 0;
'><tr><td>
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<div class='path'>path: <a href='/guix/log/?id=d3e12a02d3d682d954561de080401dfdd46ddee1'>root</a>/<a href='/guix/log/etc?id=d3e12a02d3d682d954561de080401dfdd46ddee1'>etc</a>/<a href='/guix/log/etc/source-manifest.scm?id=d3e12a02d3d682d954561de080401dfdd46ddee1'>source-manifest.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/etc/source-manifest.scm?id=d3e12a02d3d682d954561de080401dfdd46ddee1&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-09-14 11:50:58 +0200'>2021-09-14</span></td><td><a href='/guix/commit/etc/source-manifest.scm?id=3b758dd22d691964ebbc0ce9521508fbc397263a'>etc: Add 'source-manifest.scm'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/source-manifest.scm: New file.
* Makefile.am (EXTRA_DIST): Add it.
</span></span></td><td>Ludovic Courtès</td></tr>
lin.guixsd.org".</a><span class='msg-avail'>...<span class='msg-tooltip'>The guixsd.org domain is no longer advertised since before in 1.0.0
release in May 2019.

* etc/substitutes/berlin.guixsd.org.pub: Rename to...
* etc/substitutes/berlin.guix.gnu.org.pub: ... this.
* etc/substitutes/ci.guix.gnu.org.pub,
etc/substitutes/ci.guix.info.pub: Adjust accordingly.
* gnu/services/base.scm (%default-authorized-guix-keys): Likewise.
* guix/build/download-nar.scm (urls-for-item): Likewise.
* guix/self.scm (miscellaneous-files): Likewise.
* Makefile.am (dist_pkgdata_DATA): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-12-04 10:57:56 +0100'>2018-12-04</span></td><td><a href='/guix/commit/etc/substitutes/ci.guix.info.pub?id=6a837b6062ab405f6ca6d9c0163836769098d89b'>etc: Add "ci.guix.info.pub" public key file.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/substitutes/ci.guix.info.pub: New file.
* Makefile.am (dist_pkgdata_DATA): Add it.
* guix/self.scm (miscellaneous-files): Add
"share/guix/ci.guix.info.pub".
</span></span></td><td>Ludovic Courtès</td></tr>