Fix build warnings.

Test: treehugger
Change-Id: I855a6aaaa00c3020fb6b820ab11203854543a505
diff --git a/ScopedSignalHandler.h b/ScopedSignalHandler.h
index ef4473f..8cae4b6 100644
--- a/ScopedSignalHandler.h
+++ b/ScopedSignalHandler.h
@@ -50,7 +50,7 @@
     }
 
     (*handler_map_)[signal] =
-        SignalFn([=](int signal, siginfo_t* si, void* uctx) { f(*this, signal, si, uctx); });
+        SignalFn([=, this](int signal, siginfo_t* si, void* uctx) { f(*this, signal, si, uctx); });
 
     struct sigaction act {};
     act.sa_sigaction = [](int signal, siginfo_t* si, void* uctx) {
diff --git a/tests/MemUnreachable_test.cpp b/tests/MemUnreachable_test.cpp
index 8bc176b..4e2116b 100644
--- a/tests/MemUnreachable_test.cpp
+++ b/tests/MemUnreachable_test.cpp
@@ -49,7 +49,7 @@
 
 // Trick the compiler into thinking a value on the stack is still referenced.
 static void Ref(void** ptr) {
-  void** volatile storage;
+  void** volatile storage [[maybe_unused]];
   storage = ptr;
 }