package/stella: needs gcc >= 6

stella converted most of its C-Style arrays to std::array since version
6.1:
https://github.com/stella-emu/stella/commit/0c0f732e5f50b08cfcbdc5ad96c4e18ad230c04b

However, gcc 5.x does not accept a = {} initialization for std::array:

In file included from src/emucore/ConsoleIO.hxx:18:0,
                 from src/emucore/Console.hxx:34,
                 from src/gui/AudioDialog.cxx:22:
src/emucore/Control.hxx:331:71: error: array must be initialized with a brace-enclosed initializer
     std::array<bool, 5> myDigitalPinState{true, true, true, true, true};
                                                                       ^

So add a dependency on gcc >= 6 instead of trying to patch the numerous
array initializations to make them compliant with C++11

Fixes:
 - http://autobuild.buildroot.org/results/dfd9b901fabf310ed9033b8a012466c565d58684

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/stella/Config.in

@@ -3,7 +3,7 @@ config BR2_PACKAGE_STELLA
 	depends on !BR2_STATIC_LIBS # sdl2
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_TOOLCHAIN_HAS_THREADS
-	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_5 # C++14
+	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_6 # C++14
 	depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735 # exception_ptr
 	select BR2_PACKAGE_SDL2
 	select BR2_PACKAGE_LIBPNG
@@ -13,10 +13,10 @@ config BR2_PACKAGE_STELLA
 
 	  https://stella-emu.github.io/
 
-comment "stella needs a toolchain w/ dynamic library, C++, threads, gcc >= 5"
+comment "stella needs a toolchain w/ dynamic library, C++, threads, gcc >= 6"
 	depends on BR2_STATIC_LIBS || !BR2_INSTALL_LIBSTDCPP || \
 		!BR2_TOOLCHAIN_HAS_THREADS || \
-		!BR2_TOOLCHAIN_GCC_AT_LEAST_5
+		!BR2_TOOLCHAIN_GCC_AT_LEAST_6
 
 comment "stella needs a toolchain not affected by GCC bug 64735"
 	depends on BR2_TOOLCHAIN_HAS_GCC_BUG_64735