Don't build otapackage on Mac.

Also removed the unneeded variable DISTTOOLS
and the unnecessary dependency of otapackage/updatepackage on DISTTOOLS.

Bug: 23085297
Change-Id: I6b269003a72bb48eda1260c8d9b4bd88974bcde9
diff --git a/core/Makefile b/core/Makefile
index f7f6e48..100542f 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1282,7 +1282,8 @@
 # -----------------------------------------------------------------
 # host tools needed to build dist and OTA packages
 
-DISTTOOLS :=  $(HOST_OUT_EXECUTABLES)/minigzip \
+OTATOOLS :=  $(HOST_OUT_EXECUTABLES)/minigzip \
+  $(HOST_OUT_EXECUTABLES)/aapt \
   $(HOST_OUT_EXECUTABLES)/mkbootfs \
   $(HOST_OUT_EXECUTABLES)/mkbootimg \
   $(HOST_OUT_EXECUTABLES)/fs_config \
@@ -1303,7 +1304,7 @@
   $(HOST_OUT_EXECUTABLES)/boot_signer
 
 # Shared libraries.
-DISTTOOLS += \
+OTATOOLS += \
   $(HOST_LIBRARY_PATH)/libc++$(HOST_SHLIB_SUFFIX) \
   $(HOST_LIBRARY_PATH)/liblog$(HOST_SHLIB_SUFFIX) \
   $(HOST_LIBRARY_PATH)/libcutils$(HOST_SHLIB_SUFFIX) \
@@ -1317,9 +1318,6 @@
   $(HOST_LIBRARY_PATH)/libext2_quota_host$(HOST_SHLIB_SUFFIX) \
   $(HOST_LIBRARY_PATH)/libext2_uuid_host$(HOST_SHLIB_SUFFIX)
 
-OTATOOLS := $(DISTTOOLS) \
-  $(HOST_OUT_EXECUTABLES)/aapt
-
 .PHONY: otatools
 otatools: $(OTATOOLS)
 
@@ -1551,12 +1549,27 @@
 $(call dist-for-goals, target-files-package, $(BUILT_TARGET_FILES_PACKAGE))
 endif
 
-ifneq ($(SANITIZE_TARGET),address)
-ifneq ($(TARGET_PRODUCT),sdk)
-ifeq ($(filter generic%,$(TARGET_DEVICE)),)
-ifneq ($(TARGET_NO_KERNEL),true)
-ifneq ($(recovery_fstab),)
+build_ota_package := true
+ifeq ($(BUILD_OS),darwin)
+build_ota_package := false
+endif
+ifeq ($(SANITIZE_TARGET),address)
+build_ota_package := false
+endif
+ifeq ($(TARGET_PRODUCT),sdk)
+build_ota_package := false
+endif
+ifneq ($(filter generic%,$(TARGET_DEVICE)),)
+build_ota_package := false
+endif
+ifeq ($(TARGET_NO_KERNEL),true)
+build_ota_package := false
+endif
+ifeq ($(recovery_fstab),)
+build_ota_package := false
+endif
 
+ifeq ($(build_ota_package),true)
 # -----------------------------------------------------------------
 # OTA update package
 
@@ -1570,7 +1583,7 @@
 
 $(INTERNAL_OTA_PACKAGE_TARGET): KEY_CERT_PAIR := $(DEFAULT_KEY_CERT_PAIR)
 
-$(INTERNAL_OTA_PACKAGE_TARGET): $(BUILT_TARGET_FILES_PACKAGE) $(DISTTOOLS)
+$(INTERNAL_OTA_PACKAGE_TARGET): $(BUILT_TARGET_FILES_PACKAGE)
 	@echo "Package OTA: $@"
 	$(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH MKBOOTIMG=$(MKBOOTIMG) \
 	   ./build/tools/releasetools/ota_from_target_files -v \
@@ -1583,11 +1596,7 @@
 .PHONY: otapackage
 otapackage: $(INTERNAL_OTA_PACKAGE_TARGET)
 
-endif    # recovery_fstab is defined
-endif    # TARGET_NO_KERNEL != true
-endif    # TARGET_DEVICE != generic*
-endif    # TARGET_PRODUCT != sdk
-endif    # SANITIZE_TARGET != address
+endif    # build_ota_package
 
 # -----------------------------------------------------------------
 # The update package
@@ -1600,7 +1609,7 @@
 
 INTERNAL_UPDATE_PACKAGE_TARGET := $(PRODUCT_OUT)/$(name).zip
 
-$(INTERNAL_UPDATE_PACKAGE_TARGET): $(BUILT_TARGET_FILES_PACKAGE) $(DISTTOOLS)
+$(INTERNAL_UPDATE_PACKAGE_TARGET): $(BUILT_TARGET_FILES_PACKAGE)
 	@echo "Package: $@"
 	$(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH MKBOOTIMG=$(MKBOOTIMG) \
 	   ./build/tools/releasetools/img_from_target_files -v \