Add Header Library support to Make

We currently use static libraries without any source files to represent
header libraries, but Soong actually has cc_library_headers. So to
export those in a separate namespace from static libraries, implement
them in Make as well.

This also adds a nice pretty-warning / pretty-error macro that can be
used to print out standard warning messages pointing to the real source
file having the problem.

Test: Use a header library exported by Soong in a Make module
Change-Id: I3486539e247524cb82a20620745fc7be03014e14
diff --git a/core/notice_files.mk b/core/notice_files.mk
index 8a0ae6f..447e59b 100644
--- a/core/notice_files.mk
+++ b/core/notice_files.mk
@@ -36,7 +36,7 @@
   module_installed_filename := $(patsubst $(PRODUCT_OUT)/%,%,$(LOCAL_INSTALLED_MODULE))
 else
   # This module isn't installable
-  ifeq ($(LOCAL_MODULE_CLASS),STATIC_LIBRARIES)
+  ifneq ($(filter STATIC_LIBRARIES HEADER_LIBRARIES,$(LOCAL_MODULE_CLASS)),)
     # Stick the static libraries with the dynamic libraries.
     # We can't use xxx_OUT_STATIC_LIBRARIES because it points into
     # device-obj or host-obj.