diff --git a/source/shared_lib/CMakeLists.txt b/source/shared_lib/CMakeLists.txt
index 655b4e8b..2b6b5868 100644
--- a/source/shared_lib/CMakeLists.txt
+++ b/source/shared_lib/CMakeLists.txt
@@ -313,12 +313,14 @@ option(ENABLE_FRIBIDI "Enable FriBIDi support" ON)
 
                 if (NOT WIN32)
                    add_definitions (-DMINIUPNPC_SET_SOCKET_TIMEOUT)
-                   add_definitions (-D_BSD_SOURCE -D_POSIX_C_SOURCE=1)
-                endif()
+                   add_definitions (-D_BSD_SOURCE)
 
-                if (CMAKE_SYSTEM_NAME STREQUAL "Darwin")
-                   add_definitions (-DMACOSX -D_DARWIN_C_SOURCE)
-                endif ()
+                   if (CMAKE_SYSTEM_NAME STREQUAL "Darwin")
+                      add_definitions (-DMACOSX -D_DARWIN_C_SOURCE)
+                   else()
+                      add_definitions (-D_POSIX_C_SOURCE=1)
+                   endif ()
+                endif()
 
 		SET(DIRS_WITH_SRC ${DIRS_WITH_SRC} platform/miniupnpc)
 	else()