[hb-old] Start adding HarfBuzz-old as a new backend

src/Makefile.am

diff --git a/src/Makefile.am b/src/Makefile.am
index f2fce6e..757f7ca 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -8,6 +8,9 @@
 MAINTAINERCLEANFILES =
 DISTCHECK_CONFIGURE_FLAGS = --enable-introspection
 
+SUBDIRS = hb-old
+DIST_SUBDIRS = hb-old
+
 # The following warning options are useful for debugging: -Wpadded
 #AM_CXXFLAGS =
 
@@ -145,6 +148,8 @@
 HBHEADERS += hb-coretext.h
 endif
 
+HBLIBS += hb-old/libhb-old.la
+
 # Use a C linker, not C++; Don't link to libstdc++
 libharfbuzz_la_LINK = $(LINK) $(libharfbuzz_la_LDFLAGS)
 libharfbuzz_la_SOURCES = $(HBSOURCES) $(HBHEADERS)