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;
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<tr><td><span title='2022-02-02 16:46:44 +0100'>2022-02-02</span></td><td><a href='/guix/commit/gnu/installer.scm?id=4943ac86e4f95a2e14fd209f3fdaac74a0d9ca2e'>installer: Use system-wide guix for system init.</a><span class='msg-avail'>...</span></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2022-02-02 16:46:44 +0100'>2022-02-02</span></td><td><a href='/guix/commit/gnu/installer.scm?id=ad55ccf9b18000144a4e0f28a0f9e57132f94edc'>installer: Make dump archive creation optional and selective.</a><span class='msg-avail'>...</span></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2022-02-02 16:46:44 +0100'>2022-02-02</span></td><td><a href='/guix/commit/gnu/installer.scm?id=41eb0f01fcf05902be9972cc993fdb332edb928c'>installer: Use dynamic-wind to setup installer.</a><span class='msg-avail'>...</span></td><td>Josselin Poiret</td></tr>
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<tr><td><span title='2022-02-02 16:46:43 +0100'>2022-02-02</span></td><td><a href='/guix/commit/gnu/installer.scm?id=408427a36c6545115068d5f06de2ea21407374c6'>installer: Add installer-specific run command process.</a><span class='msg-avail'>...</span></td><td>Josselin Poiret</td></tr>
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<tr><td><span title='2022-02-02 16:46:42 +0100'>2022-02-02</span></td><td><a href='/guix/commit/gnu/installer.scm?id=4a68a00c8b86b999510b0cd3aaeb76c064fbcd34'>installer: Use define instead of let at top-level.</a><span class='msg-avail'>...</span></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2022-02-02 16:46:42 +0100'>2022-02-02</span></td><td><a href='/guix/commit/gnu/installer.scm?id=0d37a5df7e709cadca97cfbbf9c680dfe54b8302'>installer: Add crash dump upload support.</a><span class='msg-avail'>...</span></td><td>Mathieu Othacehe</td></tr>
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<tr><td><span title='2021-09-23 18:17:18 +0200'>2021-09-23</span></td><td><a href='/guix/commit/gnu/installer.scm?id=f34b8087411cffb0a572c0ecdce92084f0593fd4'>installer: Support XFS.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>