Workaround segfault in clang's mangling code that is tickled when
attempting to mangle the declaration:
 std:__ndk1::__find_detail::__find_exactly_one_checked::__matches
in the <tuple> header in the Android NDK.
This codepath is exercised by MozsearchIndexer.cpp (the searchfox
indexer) when indexing on Android. See also
https://bugs.llvm.org/show_bug.cgi?id=40747

diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 4420f6a2c1c3..39792e6b7350 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -3954,6 +3954,11 @@ void CXXNameMangler::mangleExpression(const Expr *E, unsigned Arity,
   // produces no output, where ImplicitlyConvertedToType and AsTemplateArg need
   // to be preserved.
 recurse:
+  if (!E) {
+    Out << "MOZ_WE_HACKED_AROUND_BUG_1500941";
+    return;
+  }
+
   switch (E->getStmtClass()) {
   case Expr::NoStmtClass:
 #define ABSTRACT_STMT(Type)