Fix Windows SDK build.

* Use gcc instead of clang in order to get proper exception support.
* Use libstdc++ instead of libc++ since gcc does not support _Atomic.
* Fix various 32/64 typing in linkloader.

Change-Id: I34abcf1e9fa98633e0fd35b4e1b71a0d5389008a
diff --git a/cpp/Android.mk b/cpp/Android.mk
index 7208789..a170a5e 100644
--- a/cpp/Android.mk
+++ b/cpp/Android.mk
@@ -18,7 +18,9 @@
 
 LOCAL_SRC_FILES := $(rs_cpp_SRC_FILES)
 
+ifneq ($(HOST_OS),windows)
 LOCAL_CLANG := true
+endif
 LOCAL_CFLAGS += $(local_cflags_for_rs_cpp)
 
 LOCAL_SHARED_LIBRARIES := \
@@ -42,7 +44,9 @@
 
 include $(CLEAR_VARS)
 
+ifneq ($(HOST_OS),windows)
 LOCAL_CLANG := true
+endif
 LOCAL_CFLAGS += $(local_cflags_for_rs_cpp)
 
 LOCAL_SDK_VERSION := 8