manpage installation updates

We should be compatible with "gem-man", as well as allowing
installation to prefix ($HOME by default) via:

	make -C Documentation install-man

1 files changed, 1 insertions, 1 deletions

diff --git a/Rakefile b/Rakefile
index 660b194..0774a09 100644
--- a/Rakefile
+++ b/Rakefile
@@ -10,7 +10,7 @@ if ! File.exist?(manifest) || File.stat(manifest).mtime < gitidx.mtime
     if system("make -C Documentation")
       require 'fileutils'
       FileUtils.rm_rf 'man'
-      if system("make -C Documentation install-man")
+      if system("make -C Documentation gem-man")
         `git ls-files -o man`.split(/\n/).each do |man|
           fp.puts man
         end