Back to symlink for the cowsay.1 man page, and do that in-repo in make man, too

The `.so` macro page produced by asciidoctor doesn't work right on some systems, including macOS and FreeBSD, and some Linuxes.

See discussion starting at: #26 (comment)

Author: apjanke

CHANGELOG.md

@@ -12,6 +12,7 @@ Cowsay Changelog
 - Fix installation location ("prefix") detection for cases like user-defined symlinks, and align repo layout with installation prefix dir layout ([#49](https://github.com/cowsay-org/cowsay/issues/49), [#55](https://github.com/cowsay-org/cowsay/issues/55))
 - Remove broken .pm cows ([#54](https://github.com/cowsay-org/cowsay/issues/54))
   - Support for the .pm cowfile format never got implemented. This keeps non-working cows from appearing in the `cowsay -l` list and the like.
+- Expand `cowsay --help` screen, and the man page a bit
 
 ### Internal changes
 

Makefile

@@ -62,13 +62,16 @@ clean:
 # install time to avoid introducing a dependency on Asciidoctor for users.
 
 .PHONY: man
-man: man/man1/cowsay.1 man/man1/cowthink.1
+man: man/man1/cowsay.1.adoc man/man1/cowsay.1
 
-man/cowsay.1: man/man1/cowsay.1.adoc
-	$(ASCIIDOCTOR) -b manpage man/man1/cowsay.1.adoc
-
-man/cowthink.1: man/man1/cowsay.1.adoc
+# asciidoctor generates both cowsay.1 and cowthink.1, but the cowthink.1 uses an '.so'
+# include macro that doesn't work on some systems, but symlinks do.
+# cowthink.1 is generated as a side effect of cowsay.1, but I'm not sure how
+# to declare that without a redundant target definition.
+man/man1/cowsay.1: man/man1/cowsay.1.adoc
 	$(ASCIIDOCTOR) -b manpage man/man1/cowsay.1.adoc
+	rm -f man/man1/cowthink.1
+	$(LN_S) cowsay.1 man/man1/cowthink.1
 
 .PHONY: install
 install:
@@ -78,7 +81,7 @@ install:
 	$(LN_S) cowsay $(DESTDIR)$(bindir)/cowthink
 	$(INSTALL_DIR) $(DESTDIR)$(mandir)/man1
 	$(INSTALL_DATA) man/man1/cowsay.1 $(DESTDIR)$(mandir)/man1/cowsay.1
-	$(INSTALL_DATA) man/man1/cowthink.1 $(DESTDIR)$(mandir)/man1/cowthink.1
+	$(LN_S) cowsay.1 $(DESTDIR)$(mandir)/man1/cowthink.1
 	$(INSTALL_DIR) $(DESTDIR)$(cowsdir)
 	$(INSTALL_DATA) $(COW_FILES) $(DESTDIR)$(cowsdir)
 	$(INSTALL_DIR) $(DESTDIR)$(sitecowsdir)

man/man1/cowthink.1

@@ -0,0 +1 @@
+cowsay.1