remove dependency of sslh-conf.c to sslhconf.cfg (fix #283)

Makefile

@@ -88,8 +88,12 @@ sslh: sslh-fork sslh-select sslh-ev
 $(OBJS) $(FORK_OBJS) $(SELECT_OBJS) $(EV_OBJS): argtable3.h collection.h common.h gap.h hash.h log.h probe.h processes.h sslh-conf.h tcp-listener.h tcp-probe.h tls.h udp-listener.h version.h
 
 
-sslh-conf.c sslh-conf.h: sslhconf.cfg
+c2s:
 	conf2struct sslhconf.cfg
+	conf2struct echosrv.cfg
+
+sslh-conf.c sslh-conf.h: sslhconf.cfg
+	$(warning "sslhconf.cfg is more recent than sslh-conf.[ch]. Use `make c2s` to rebuild using `conf2struct`")
 
 sslh-fork: version.h Makefile $(FORK_OBJS)
 	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-fork $(FORK_OBJS) $(LIBS)
@@ -104,7 +108,7 @@ systemd-sslh-generator: systemd-sslh-generator.o
 	$(CC) $(CFLAGS) $(LDFLAGS) -o systemd-sslh-generator systemd-sslh-generator.o -lconfig
 
 echosrv-conf.c echosrv-conf.h: echosrv.cfg
-	conf2struct echosrv.cfg
+	$(warning "echosrv.cfg is more recent than echosrv-conf.[ch]. Use `make c2s` to rebuild using `conf2struct`")
 
 echosrv: version.h echosrv-conf.c echosrv.o echosrv-conf.o argtable3.o
 	$(CC) $(CFLAGS) $(LDFLAGS) -o echosrv echosrv.o echosrv-conf.o argtable3.o $(LIBS)

doc/INSTALL.md

@@ -79,6 +79,20 @@ of the Makefile:
 * `USELIBBSD` compiles support for updating the process name (as shown
   by `ps`).
 
+Generating the configuration parser
+-----------------------------------
+
+The configuration file and command line parser is generated
+by `conf2struct`, from `sslhconf.cfg`, which generates
+`sslh-conf.c` and `sslh-conf.h`. The resulting files are
+included in the source so `sslh` can be built without
+`conf2struct` installed.
+
+Further, to prevent build issues, `sslh-conf.[ch]` has no
+dependency to `sslhconf.cfg` in the Makefile.  In the event
+of adding configuration settings, they need to be
+regenerated using `make c2s`.
+
 Binaries
 --------