OpenSP: use catalogs from Homebrew prefix

Added configure flags to OpenSP to use its default catalog in
/usr/local/share/sgml. OpenJade searches for catalogs in this path
only if it is configured in OpenSP too.

Closes Homebrew/homebrew#15955.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/open-sp.rb

@@ -9,7 +9,9 @@ class OpenSp < Formula
     system "./configure", "--disable-debug", "--disable-dependency-tracking",
                           "--prefix=#{prefix}",
                           "--mandir=#{man}",
-                          "--disable-doc-build"
-    system "make install"
+                          "--disable-doc-build",
+                          "--enable-default-catalog=#{HOMEBREW_PREFIX}/share/sgml/catalog",
+                          "--enable-default-search-path=#{HOMEBREW_PREFIX}/share/sgml"
+    system "make", "pkgdatadir=#{share}/sgml/opensp", "install"
   end
 end