ruby: osx support (maybe)

plugins/ruby/CMakeLists.txt

@@ -1,5 +1,5 @@
 OPTION(DL_RUBY "download libruby from the internet" ON)
-IF (DL_RUBY)
+IF (DL_RUBY AND NOT APPLE)
     IF (UNIX)
         FILE(DOWNLOAD http://cloud.github.com/downloads/jjyg/dfhack/libruby187.tar.gz ${CMAKE_CURRENT_SOURCE_DIR}/libruby187.tar.gz
             EXPECTED_MD5 eb2adea59911f68e6066966c1352f291)
@@ -15,7 +15,7 @@ IF (DL_RUBY)
         FILE(RENAME msvcrt-ruby18.dll libruby.dll)
         SET(RUBYLIB libruby.dll)
     ENDIF(UNIX)
-ENDIF(DL_RUBY)
+ENDIF(DL_RUBY AND NOT APPLE)
 
 ADD_CUSTOM_COMMAND(
     OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/ruby-autogen.rb
@@ -35,4 +35,3 @@ INSTALL(FILES ${RUBYLIB} DESTINATION ${DFHACK_LIBRARY_DESTINATION})
 INSTALL(DIRECTORY .
         DESTINATION hack/ruby
         FILES_MATCHING PATTERN "*.rb")
-

plugins/ruby/ruby.cpp

@@ -262,8 +262,10 @@ DFHack::DFLibrary *libruby_handle;
 static int df_loadruby(void)
 {
     const char *libpath =
-#ifdef WIN32
+#if defined(WIN32)
         "./libruby.dll";
+#elif defined(__APPLE__)
+	"/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/libruby.1.dylib";
 #else
         "hack/libruby.so";
 #endif