Export libicuuc_headers

This allows vendor modules to include headers via VNDK-compliant way
LOCAL_HEADER_LIBRARIES += libicuuc_headers
rather than old way
LOCAL_C_INCLUDES += external/icu/icu4c/source/common

Bug: 36529495
Test: Build sailfish
Change-Id: Id2399444d3e588f86c8e97a14bd11fd87f4e54dd
diff --git a/icu4c/source/common/Android.bp b/icu4c/source/common/Android.bp
index 9555db7..c363798 100644
--- a/icu4c/source/common/Android.bp
+++ b/icu4c/source/common/Android.bp
@@ -258,3 +258,9 @@
     defaults: ["libicuuc_defaults"],
     static_libs: ["libicuuc_stubdata"],
 }
+
+cc_library_headers {
+    name: "libicuuc_headers",
+    host_supported: true,
+    export_include_dirs: ["."],
+}