contrib: remove Winphone specific flag

We don't support it anymore and that platform is dead. We don't
even use the flag to enable/disable anything.

contrib/bootstrap

@@ -322,11 +322,6 @@ case "${OS}" in
 		;;
 	*mingw*)
 		add_make_enabled "HAVE_WIN32"
-		case "${HOST}" in
-			*winphone*|*windowsphone*)
-				add_make_enabled "HAVE_WINDOWSPHONE"
-				;;
-		esac
 		case "${HOST}" in
 			*winphone*|*windowsphone*|*winrt*|*uwp*)
 				add_make_enabled "HAVE_WINSTORE"

contrib/src/main.mak

@@ -646,9 +646,6 @@ ifdef HAVE_VISUALSTUDIO
 ifdef HAVE_WINSTORE
 CMAKE_SYSTEM_NAME = WindowsStore
 endif
-ifdef HAVE_WINDOWSPHONE
-CMAKE_SYSTEM_NAME = WindowsPhone
-endif
 endif
 endif
 ifdef HAVE_DARWIN_OS