Add UPnP support.

Feedback is in logs as suggested by skid_au. The checkbox is still there, but
mostly for people who would like to opt out (unfortunately, I can not be sure
how this feature may behave for some routers - there's a hell of a lot of bad
UPnP implementations.)

The Visual Studio stuff is a little messy, so I apologize if anything is a bit
off. I tested most configurations and it worked.

I also tested CMake on Debian Wheezy, Ubuntu Saucy, and Mac OS X Mountain Lion.
All seemed to be OK.

CMakeLists.txt

@@ -9,6 +9,7 @@ option(USE_X11 "Enables X11 Support" ON)
 option(USE_WAYLAND "Enables Wayland Support" OFF)
 option(USE_GLES "Enables GLES2 And EGL, disables OGL" OFF)
 option(USE_GLES3 "Enables GLES3 and EGL" OFF)
+option(USE_UPNP "Enables UPnP port mapping support" ON)
 option(DISABLE_WX "Disable wxWidgets (use CLI interface)" OFF)
 
 option(FASTLOG "Enable all logs" OFF)
@@ -549,6 +550,13 @@ else()
        include_directories(Externals/SFML/include)
 endif()
 
+if(USE_UPNP)
+	message("Using static MiniUPnP client from Externals")
+	add_subdirectory(Externals/miniupnpc)
+	include_directories(Externals/miniupnpc/src)
+	add_definitions(-DUSE_UPNP)
+endif()
+
 if(NOT ${CMAKE_SYSTEM_NAME} MATCHES "Darwin" AND NOT ANDROID)
 	check_lib(SOIL SOIL SOIL/SOIL.h QUIET)
 endif()

Externals/miniupnpc/CMakeLists.txt

@@ -0,0 +1,37 @@
+cmake_minimum_required(VERSION 2.6)
+
+project(miniupnpc C)
+set(MINIUPNPC_VERSION 1.7)
+set(MINIUPNPC_API_VERSION 9)
+
+if(UNIX)
+	add_definitions(-DMINIUPNPC_SET_SOCKET_TIMEOUT)
+	add_definitions(-D_BSD_SOURCE -D_POSIX_C_SOURCE=1)
+elseif(WIN32)
+	add_definitions(-D_WIN32_WINNT=0x0501)
+	find_library(WINSOCK2_LIBRARY NAMES ws2_32 WS2_32 Ws2_32)
+	find_library(IPHLPAPI_LIBRARY NAMES iphlpapi)
+	set(LDLIBS ${WINSOCK2_LIBRARY} ${IPHLPAPI_LIBRARY} ${LDLIBS})
+endif()
+
+if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
+	add_definitions(-DMACOSX -D_DARWIN_C_SOURCE)
+endif()
+
+include_directories(include)
+
+set(SRCS	src/igd_desc_parse.c
+			src/miniupnpc.c
+			src/minixml.c
+			src/minisoap.c
+			src/miniwget.c
+			src/upnpc.c
+			src/upnpcommands.c
+			src/upnpreplyparse.c
+			src/upnperrors.c
+			src/connecthostport.c
+			src/portlistingparse.c
+			src/receivedata.c)
+
+add_library(miniupnpc STATIC ${SRCS})
+