Don't build nTox by default.

Build it on Travis. It won't be built on the windows builds regardless
of having it enabled globally.

Fixes TokTok#292.

CMakeLists.txt

@@ -483,8 +483,8 @@ if(NOT WIN32
   endif()
 endif()
 
-option(BUILD_NTOX "Build nTox client" ON)
-if(NOT WIN32 AND BUILD_NTOX)
+option(BUILD_NTOX "Build nTox client" OFF)
+if(BUILD_NTOX AND NOT WIN32)
   add_c_executable(nTox testing/nTox.c)
   target_link_modules(nTox toxcore ${NCURSES_LIBRARIES})
 endif()

other/travis/env.sh

@@ -7,7 +7,7 @@ export LD_LIBRARY_PATH=$CACHE_DIR/lib
 export PKG_CONFIG_PATH=$CACHE_DIR/lib/pkgconfig
 export ASTYLE=$CACHE_DIR/astyle/build/gcc/bin/astyle
 export CFLAGS="-O3 -DTRAVIS_ENV=1"
-export CMAKE_EXTRA_FLAGS="-DERROR_ON_WARNING=ON"
+export CMAKE_EXTRA_FLAGS="-DERROR_ON_WARNING=ON -DBUILD_NTOX=ON"
 
 BUILD_DIR=_build