Fixed: don't use GNU linker options with BSD's linker installed on mac os x

code/CMakeModules/nel.cmake

@@ -274,7 +274,9 @@ MACRO(NL_SETUP_BUILD)
     IF(WITH_COVERAGE)
       SET(PLATFORM_CFLAGS "-fprofile-arcs -ftest-coverage ${PLATFORM_CFLAGS}")
     ENDIF(WITH_COVERAGE)
-    SET(PLATFORM_LINKFLAGS "-Wl,--no-undefined -Wl,--as-needed")
+    IF(NOT APPLE)
+      SET(PLATFORM_LINKFLAGS "-Wl,--no-undefined -Wl,--as-needed")
+    ENDIF(NOT APPLE)
     SET(NL_DEBUG_CFLAGS "-DNL_DEBUG -g")
     SET(NL_RELEASE_CFLAGS "-DNL_RELEASE -O6 -g")
     SET(NL_NONE_CFLAGS "-DNL_RELEASE -g -finline-functions -O2 ")