Compile ICU4C with clang.

Note that the icu NDK targets appear unused, but i'll delete
them in a separate change since they might be used in some obscure
unbundled branch that isn't indexed.

Change-Id: Idfa19cabaef61f7ac86ac8e0ec136d918131b432
diff --git a/icu4c/source/common/Android.mk b/icu4c/source/common/Android.mk
index d3f55e9..a8bab99 100644
--- a/icu4c/source/common/Android.mk
+++ b/icu4c/source/common/Android.mk
@@ -151,6 +151,7 @@
 LOCAL_ADDITIONAL_DEPENDENCIES += $(LOCAL_PATH)/Android.mk
 LOCAL_REQUIRED_MODULES += icu-data
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
+LOCAL_CLANG := true
 include $(BUILD_SHARED_LIBRARY)
 
 #
@@ -169,6 +170,7 @@
 LOCAL_REQUIRED_MODULES += icu-data-host
 LOCAL_MULTILIB := both
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
+LOCAL_CLANG := true
 include $(BUILD_HOST_SHARED_LIBRARY)
 
 #
@@ -189,4 +191,5 @@
 LOCAL_MODULE := libicuuc_static
 LOCAL_SRC_FILES += $(src_files)
 LOCAL_REQUIRED_MODULES += icu-data
+LOCAL_CLANG := true
 include $(BUILD_STATIC_LIBRARY)
diff --git a/icu4c/source/i18n/Android.mk b/icu4c/source/i18n/Android.mk
index de588d2..da5b050 100644
--- a/icu4c/source/i18n/Android.mk
+++ b/icu4c/source/i18n/Android.mk
@@ -132,6 +132,7 @@
 LOCAL_MODULE := libicui18n
 LOCAL_ADDITIONAL_DEPENDENCIES += $(LOCAL_PATH)/Android.mk
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
+LOCAL_CLANG := true
 include $(BUILD_SHARED_LIBRARY)
 
 
@@ -150,6 +151,7 @@
 LOCAL_ADDITIONAL_DEPENDENCIES += $(LOCAL_PATH)/Android.mk
 LOCAL_MULTILIB := both
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
+LOCAL_CLANG := true
 include $(BUILD_HOST_SHARED_LIBRARY)
 
 #
@@ -171,4 +173,5 @@
 LOCAL_EXPORT_CFLAGS += -DU_STATIC_IMPLEMENTATION=1
 LOCAL_MODULE_TAGS := optional
 LOCAL_MODULE := libicui18n_static
+LOCAL_CLANG := true
 include $(BUILD_STATIC_LIBRARY)