[msan] don't check shadow inside interceptors if we are inside symbolizer; add weak function __msan_default_options that overrides default options

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@175040 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/msan/msan.h b/lib/msan/msan.h
index eafe702..d612bfb 100644
--- a/lib/msan/msan.h
+++ b/lib/msan/msan.h
@@ -46,6 +46,10 @@
 void InstallAtExitHandler();
 void ReplaceOperatorsNewAndDelete();
 
+void EnterSymbolizer();
+void ExitSymbolizer();
+bool IsInSymbolizer();
+
 void MsanDie();
 void PrintWarning(uptr pc, uptr bp);
 void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin);