Merge remote-tracking branch 'TC01/ruby-no-dl-flag' into develop

plugins/ruby/CMakeLists.txt

@@ -1,3 +1,8 @@
+# Allow build system to turn off downloading of libruby.so.
+OPTION(DOWNLOAD_RUBY "Download prebuilt libruby.so for ruby plugin." ON)
+
+IF (DOWNLOAD_RUBY)
+
     IF (APPLE)
         SET(RUBYLIB ${CMAKE_CURRENT_SOURCE_DIR}/osx${DFHACK_BUILD_ARCH}/libruby.dylib)
         SET(RUBYLIB_INSTALL_NAME "libruby.dylib")
@@ -49,6 +54,8 @@ ELSE()
         ENDIF()
     ENDIF()
 
+ENDIF()
+
 IF (APPLE OR UNIX)
     SET(RUBYAUTOGEN ruby-autogen-gcc.rb)
 ELSE (APPLE OR UNIX)
@@ -73,7 +80,8 @@ ADD_DEPENDENCIES(ruby ruby-autogen-rb)
 IF(EXISTS ${RUBYLIB})
     INSTALL(FILES ${RUBYLIB} DESTINATION ${DFHACK_LIBRARY_DESTINATION} RENAME ${RUBYLIB_INSTALL_NAME})
 ELSE()
-    IF(NOT(APPLE AND ${DFHACK_BUILD_ARCH} STREQUAL 64))
+    # Only fire this warning if DOWNLOAD_RUBY was set.
+    IF(NOT(APPLE AND ${DFHACK_BUILD_ARCH} STREQUAL 64) AND DOWNLOAD_RUBY)
         MESSAGE(WARNING "Ruby library not found at ${RUBYLIB} - will not be installed")
     ENDIF()
 ENDIF()