Implement android::base::WaitForProperty.

Also adapt libcutils to the bionic change that was necessary for this.

Bug: http://b/35201172
Test: ran tests
Change-Id: I72a98b70b03d23e958b46778b505fbd5c86c32ae
diff --git a/libcutils/properties.cpp b/libcutils/properties.cpp
index 43ad574..d2645e6 100644
--- a/libcutils/properties.cpp
+++ b/libcutils/properties.cpp
@@ -129,7 +129,7 @@
     void* cookie;
 };
 
-static void trampoline(void* raw_data, const char* name, const char* value) {
+static void trampoline(void* raw_data, const char* name, const char* value, unsigned /*serial*/) {
     callback_data* data = reinterpret_cast<callback_data*>(raw_data);
     data->callback(name, value, data->cookie);
 }