Improve Makefile to avoid "Argument list too long" error

I wouldn't expect a foreach loop to be prone to this issue but it's
not the right way to write a Makefile anyway.

Note that conversion failures are now fatal and the dvb-t/ke-Nairobi
file is failing to convert at the moment.

Signed-off-by: James Le Cuirot <chewi@gentoo.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Makefile

@@ -17,6 +17,8 @@ DVBV3DIRS = atsc dvb-c dvb-s dvb-t
 DVBV5DIRS = $(DVBV3DIRS) isdb-t
 
 DVBV3CHANNELFILES = $(foreach dir,$(DVBV3DIRS),$(wildcard $(dir)/*))
+DVBV3OUTPUTFILES = $(patsubst %,$(DVBV3OUTPUTDIR)/%,$(DVBV3CHANNELFILES))
+DVBV5OUTPUTFILES = $(patsubst %,$(DVBV5OUTPUTDIR)/%,$(DVBV3CHANNELFILES))
 
 DVBFORMATCONVERT_CHANNEL_DVBV5 = -ICHANNEL -ODVBV5
 DVBFORMATCONVERT_CHANNEL_DVBV3 = -IDVBV5 -OCHANNEL
@@ -42,14 +44,16 @@ ifeq ($(DVBV3DIR),)
 DVBV3DIR = dvbv3
 endif
 
-dvbv3:
-	@$(foreach var,$(DVBV3DIRS), $(MKDIR) $(DVBV3OUTPUTDIR)/$(var);)
-	@$(foreach var,$(DVBV3CHANNELFILES), $(DVBFORMATCONVERT) $(DVBFORMATCONVERT_CHANNEL_DVBV3) $(var) $(DVBV3OUTPUTDIR)/$(var);)
+$(DVBV3OUTPUTFILES): $(DVBV3OUTPUTDIR)/%: %
+	@$(MKDIR) "$(dir $@)"
+	@$(DVBFORMATCONVERT) $(DVBFORMATCONVERT_CHANNEL_DVBV3) "$<" "$@"
 
+$(DVBV5OUTPUTFILES): $(DVBV5OUTPUTDIR)/%: $(DVBV3OUTPUTDIR)/%
+	@$(MKDIR) "$(dir $@)"
+	@$(DVBFORMATCONVERT) $(DVBFORMATCONVERT_CHANNEL_DVBV5) "$<" "$@"
 
-dvbv5: $(DVBV3OUTPUTDIR)
-	@$(foreach var,$(DVBV3DIRS), $(MKDIR) $(DVBV5OUTPUTDIR)/$(var);)
-	@$(foreach var,$(DVBV3CHANNELFILES), $(DVBFORMATCONVERT) $(DVBFORMATCONVERT_CHANNEL_DVBV5) $(DVBV3OUTPUTDIR)/$(var) $(DVBV5OUTPUTDIR)/$(var);)
+dvbv3: $(DVBV3OUTPUTFILES)
+dvbv5: $(DVBV5OUTPUTFILES)
 
 install:
 	@mkdir -p $(DATADIR)/$(DVBV5DIR)