fix OSX package names is OSX_DEPLOYMENT_TARGET is specified

cmake/package_name.cmake

@@ -72,14 +72,15 @@ IF(NOT VERSION)
         ENDIF()
       ENDIF()
     ELSEIF(CMAKE_SYSTEM_NAME MATCHES "Darwin")
-      IF(${CMAKE_OSX_DEPLOYMENT_TARGET})
-        SET(VER "${CMAKE_OSX_DEPLOYMENT_TARGET}")
+      IF(CMAKE_OSX_DEPLOYMENT_TARGET)
+        SET(DEFAULT_PLATFORM "osx${CMAKE_OSX_DEPLOYMENT_TARGET}")
       ELSE()
         SET(VER "${CMAKE_SYSTEM_VERSION}")
+        STRING(REGEX REPLACE "([0-9]+)\\.[0-9]+\\.[0-9]+" "\\1" VER "${VER}")
+        # Subtract 4 from Darwin version to get correct osx10.X
+        MATH(EXPR VER  "${VER} -4")
+        SET(DEFAULT_PLATFORM "osx10.${VER}")
       ENDIF()
-      STRING(REGEX REPLACE "([0-9]+)\\.[0-9]+\\.[0-9]+" "\\1" VER "${VER}")
-      MATH(EXPR VER  "${VER} -4")
-      SET(DEFAULT_PLATFORM "osx10.${VER}")
       LIST(LENGTH CMAKE_OSX_ARCHITECTURES LEN)
       IF(LEN GREATER 1)
         SET(DEFAULT_MACHINE "universal")