Remove legacy windows platform build support

We still support HOST_OS=windows for the SDK host tools cross-builds, but
that's only when USE_MINGW is set when running under linux.

Change-Id: I37da87dc9fbbd69ba10ce4d7f2668ab3f6482d92
diff --git a/core/definitions.mk b/core/definitions.mk
index 35e3a79..0f5aed3 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1645,11 +1645,7 @@
     $(addprefix --rename-instrumentation-target-package , $(PRIVATE_MANIFEST_INSTRUMENTATION_FOR))
 endef
 
-ifeq ($(HOST_OS),windows)
-xlint_unchecked :=
-else
 xlint_unchecked := -Xlint:unchecked
-endif
 
 ifeq (true, $(ENABLE_INCREMENTALJAVAC))
 incremental_dex := --incremental
@@ -1988,13 +1984,12 @@
 
 #TODO: use a smaller -Xmx value for most libraries;
 #      only core.jar and framework.jar need a heap this big.
-# Avoid the memory arguments on Windows, dx fails to load for some reason with them.
 define transform-classes.jar-to-dex
 @echo "target Dex: $(PRIVATE_MODULE)"
 @mkdir -p $(dir $@)
 $(hide) rm -f $(dir $@)classes*.dex
 $(hide) $(DX) \
-    $(if $(findstring windows,$(HOST_OS)),,-JXms16M -JXmx2048M) \
+    -JXms16M -JXmx2048M \
     --dex --output=$(dir $@) \
     $(incremental_dex) \
     $(if $(NO_OPTIMIZE_DX), \