Fix actual errors and remove warnings suppressions.

Bug: 21764905

This got missed during 64-bit bringup last year. These functions are
safe to sidestep, since RenderScript does not use C++ modules. We still
have to declare/define them because of Clang's interface here. The other
-Wno* warning suppressions were unused, so I am removing those as well.

Change-Id: I9dba84f124fad3eade5f0a3f3025a9fb2bba1f7c
diff --git a/Android.mk b/Android.mk
index 5e2afb5..e0556e2 100644
--- a/Android.mk
+++ b/Android.mk
@@ -20,8 +20,7 @@
 ifeq ($(TARGET_BUILD_APPS),)
 
 
-local_cflags_for_slang := -Wno-sign-promo -Wall -Wno-unused-parameter \
-                          -Wno-return-type -Werror -std=c++11
+local_cflags_for_slang := -Wall -Werror -std=c++11
 ifeq ($(TARGET_BUILD_VARIANT),eng)
 local_cflags_for_slang += -O0
 else
diff --git a/slang.h b/slang.h
index c220beb..0848451 100644
--- a/slang.h
+++ b/slang.h
@@ -275,10 +275,16 @@
                          bool Complain = false) override {}
 
   clang::GlobalModuleIndex *
-  loadGlobalModuleIndex(clang::SourceLocation TriggerLoc) override {}
+  loadGlobalModuleIndex(clang::SourceLocation TriggerLoc) override {
+    // We don't support C++ modules for RenderScript.
+    return nullptr;
+  }
 
   bool lookupMissingImports(llvm::StringRef Name,
-                            clang::SourceLocation TriggerLoc) override {}
+                            clang::SourceLocation TriggerLoc) override {
+    // We don't support C++ modules for RenderScript.
+    return false;
+  }
 };
 
 } // namespace slang