see https://savannah.gnu.org/bugs/index.php?68505
fix parallel with ttf that requires bdf files
--- a/font/Makefile
+++ b/font/Makefile
@@ -1385,7 +1385,7 @@ truetype-stamp: ttf-stamp ttf-csur-stamp ttf-upper-stamp
 #
 ttf: ttf-stamp
 
-ttf-stamp: hex-stamp
+ttf-stamp: hex-stamp bdf-stamp
 	# First, copy the ordinary version, to make a TrueType font.
 	# Remove the Variation Selectors, U+FE00..U+FE0F
 	grep -v "^FE0.:" $(COMPILED_DIR)/unifont-$(VERSION).hex \
@@ -1474,7 +1474,7 @@ ttf-csur-stamp: hex-stamp
 #
 ttf-upper: ttf-upper-stamp
 
-ttf-upper-stamp: hex-stamp
+ttf-upper-stamp: hex-stamp bdf-stamp
 	# First, copy the ordinary version, to make a TrueType font.
 	# Remove Variation Selectors, U+E0100..U+E01EF.
 	grep -v "^0E01[0-E].:" $(COMPILED_DIR)/unifont_upper-$(VERSION).hex \