Add "Macaulay2-docs" library for installing pre-generated docs

Passing "--enable-documentation=download" to configure will install
it.

Author: d-torrance

M2/configure.ac

@@ -219,14 +219,18 @@ fi
 AC_ARG_ENABLE([documentation],
     [AS_HELP_STRING([--enable-documentation=...],
         [space-delimited list of types of documentation to build; available
-         options are "html", "info", and "pdf"; default value is "html info"])],
+         options are "html", "info", and "pdf"; default value is "html info".
+         "download" will download pre-generated documentation])],
     [DOCUMENTATION=$enableval],
     [DOCUMENTATION="html info"])
 
 if test "$DOCUMENTATION" = no
 then DOCUMENTATION=""
 elif test "$DOCUMENTATION" = yes
 then DOCUMENTATION="html info"
+elif test "$DOCUMENTATION" = download
+then DOCUMENTATION=""
+     BUILDLIST="$BUILDLIST Macaulay2-docs"
 else for DOCTYPE in $DOCUMENTATION
     do case $DOCTYPE in
             html|pdf)

M2/libraries/Macaulay2-docs/Makefile.in

@@ -0,0 +1,8 @@
+VERSION = @PACKAGE_VERSION@
+
+CONFIGURECMD = :
+
+INSTALLTARGET = install prefix=@pre_prefix@ exec_prefix=@pre_exec_prefix@
+
+include ../Makefile.library
+Makefile: @srcdir@/Makefile.in ; cd ../.. && ./config.status libraries/Macaulay2-docs/Makefile

M2/libraries/Makefile.in

@@ -4,7 +4,7 @@ BUILT_TARGETS = patch fetch all check unconfigure reinstall
 ALL_TARGETS = $(BUILT_TARGETS) clean distclean
 all:fetch
 $(ALL_TARGETS): Makefile.library
-$(foreach d,@LIBLIST@ @PROGLIST@ libtool M2,		\
+$(foreach d,@LIBLIST@ @PROGLIST@ M2 Macaulay2-docs,	\
 	$(foreach t, $(ALL_TARGETS),			\
 		$(eval $t-in-$d:; + $$(MAKE) -C $d $t)	\
 		$(eval .PHONY: $t $t-in-$d)))

M2/m4/files

@@ -25,6 +25,7 @@ distributions/deb/macaulay2/preinst
 libraries/Makefile
 libraries/4ti2/Makefile
 libraries/M2/Makefile
+libraries/Macaulay2-docs/Makefile
 libraries/Makefile.library
 libraries/cddlib/Makefile
 libraries/cddplus/Makefile