Merge with GCC. Eliminate quilt bits.

include/Makefile.am

@@ -5,5 +5,8 @@ AUTOMAKE_OPTIONS=foreign
 DISTCLEANFILES=ffitarget.h
 EXTRA_DIST=ffi.h.in ffi_common.h
 
-includesdir = $(libdir)/@PACKAGE_NAME@-@PACKAGE_VERSION@/include
-nodist_includes_HEADERS = ffi.h ffitarget.h
+# Where generated headers like ffitarget.h get installed.
+gcc_version   := $(shell cat $(top_srcdir)/../gcc/BASE-VER)
+toollibffidir := $(libdir)/gcc/$(target_alias)/$(gcc_version)/include
+
+toollibffi_HEADERS = ffi.h ffitarget.h