Add make rule to build hb.cc
Part of https://github.com/harfbuzz/harfbuzz/issues/1809
diff --git a/src/Makefile.am b/src/Makefile.am
index e7b279d..c276118 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -303,6 +303,12 @@
$(AM_V_GEN)(cd $(srcdir) && $(RAGEL) -e -F1 -o "$*.hh" "$*.rl") \
|| ($(RM) "$@"; false)
+hb.cc: Makefile.sources
+ $(AM_V_GEN) \
+ for f in $(HB_BASE_sources); do echo '#include "'$$f'"'; done | \
+ grep '[.]cc"' > $(srcdir)/hb.cc \
+ || ($(RM) $(srcdir)/hb.cc; false)
+
noinst_PROGRAMS = \
main \
test \