Add man pages

Makefile

@@ -16,6 +16,10 @@ checkproof: $(checkproof_objects)
 	@printf 'CCLD\t$@\n'
 	@$(CC) $(LDFLAGS) -o $@ $(checkproof_objects)
 
+doc/mkchallenge.1: doc/mkchallenge.scd
+doc/mkproof.1: doc/mkproof.scd
+doc/checkproof.1: doc/checkproof.scd
+
 .SUFFIXES: .c .o .scd .1 .5
 
 .c.o:
@@ -25,7 +29,11 @@ checkproof: $(checkproof_objects)
 		$(CPP) $(CFLAGS) -MM -MT $@ $< >> $(OUTDIR)/cppcache
 	@$(CC) -c $(CFLAGS) -o $@ $<
 
-docs:
+.scd.1:
+	@printf 'SCDOC\t$@\n'
+	@$(SCDOC) < $< > $@
+
+docs: doc/mkchallenge.1 doc/mkproof.1 doc/checkproof.1
 
 clean:
 	@rm -f \

doc/checkproof.scd

@@ -0,0 +1,15 @@
+checkproof(1)
+
+# NAME
+
+*checkproof* - verify a proof-of-work challenge
+
+# SYNOPSIS
+
+*checkproof* _challenge_ _proof_
+
+# DESCRIPTION
+
+*checkproof* verifies a proof-of-work challenge which has been completed by
+*mkproof*(1). The result will be printed to stdout. If valid, *checkproof* will
+exit with a zero status code; if invalid, a nonzero status code.

doc/mkchallenge.scd

@@ -0,0 +1,20 @@
+mkchallenge(1)
+
+# NAME
+
+*mkchallenge* - generate a proof-of-work challenge
+
+# SYNOPSIS
+
+*mkchallenge* [-d _difficulty_]
+
+# DESCRIPTION
+
+*mkchallenge* generates a proof-of-work challenge and prints it to stdout. To
+solve the challenge, see *mkproof*(1). To check the solution, see
+*checkproof*(1).
+
+# OPTIONS
+
+*-d* _difficulty_
+	Sets the challenge difficulty. The default is 4.

doc/mkproof.scd

@@ -0,0 +1,18 @@
+mkproof(1)
+
+# NAME
+
+*mkproof* - complete a proof-of-work challenge
+
+# SYNOPSIS
+
+*mkproof* _challenge_
+
+# DESCRIPTION
+
+*mkproof* completes a proof-of-work challenge prepared by *mkchallenge*(1). The
+proof will be printed to stdout once it is obtained, and may be passed to
+*checkproof*(1) for verification.
+
+This command is computationally expensive, and will likely pin a CPU core. See
+*nice*(1) to constrain its performance characteristics.