swi-prolog - fix jni.h issue & improve X11 support

Formula no longer includes JPL by default to get around an error that
Apple's introduced in OSX 10.6 with broken symlinks to the JNI .h files.
Also, now checks for X11 and disables xpce if required, and uses the
Homebrew ENV.x11 system to include the appropriate libraries and
headers.

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

Formula/swi-prolog.rb

@@ -10,24 +10,46 @@ class SwiProlog <Formula
   depends_on 'gmp'
   depends_on 'jpeg'
   depends_on 'fontconfig' if MACOS_VERSION < 10.6
-  depends_on 'ncursesw'
   depends_on 'mcrypt'
   depends_on 'gawk'
 
   def options
-    [['--lite', "Don't install any packages"]]
+    [['--lite', "Don't install any packages; overrides --with-jpl"],
+     ['--with-jpl', "Include JPL, the Java-Prolog Bridge"]]
   end
 
   def install
-    ENV['CIFLAGS'] = ENV['CPPFLAGS']
-    if ARGV.include? '--lite'
-      world = ''
-    else
-      world = '--with-world'
+    args = ["--prefix=#{prefix}", "--mandir=#{man}"]
+
+    # It looks like Apple has borked the Java JNI headers in Java 1.6.0_22-b04-37.
+    # Will not install the JPL bridge by default, which depends on them.
+    unless ARGV.include? "--with-jpl"
+      ohai <<-EOS.undent
+        JPL, the Java-Prolog bridge, is not installed by this formula by default.
+        If you want to indclude the Java-Prolog bridge, add the --with-jpl option.
+      EOS
+
+      ENV.append 'DISABLE_PKGS', "jpl"
     end
 
-    system "./configure", "--prefix=#{prefix}", world, "--x-includes=/usr/X11/include",
-                          "--x-libraries=/usr/X11/lib", "--mandir=#{man}"
+    if x11_installed?
+      # SWI-Prolog requires X11 for XPCE
+      ENV.x11
+    else
+      opoo  "It appears that X11 is not installed. The XPCE packages will not be built."
+      ENV.append 'DISABLE_PKGS', "xpce"
+    end
+
+    # SWI-Prolog's Makefiles don't add CPPFLAGS to the compile command, but do
+    # include CIFLAGS. Setting it here. Also, they clobber CFLAGS, so including
+    # the Homebrew-generated CFLAGS into COFLAGS here.
+    ENV['CIFLAGS'] = ENV['CPPFLAGS']
+    ENV['COFLAGS'] = ENV['CFLAGS']
+
+    # Build the packages unless --lite option specified
+    args << "--with-world" unless ARGV.include? "--lite"
+
+    system "./configure", *args
     system "make"
     system "make install"
   end