Use C++17 to compile 0 A.D.

Supported compilers are Clang 5, GCC 7, Visual Studio 17, Xcode 9.3

Update Atlas alongside since the replacement APIs are c++17 only.
De-activate the StyledTextCtrl module of WxWidgets on mac, since that is
a wrapper around the Scintilla Text editor and doesn't compile with
C++17 (as it uses auto_ptr). We don't use the editor, so this is also a
win on the compilation time front.

Closes #5862

Differential Revision: https://code.wildfiregames.com/D3166
This was SVN commit r24308.

libraries/osx/build-osx-libs.sh

@@ -86,7 +86,7 @@ if [[ $MIN_OSX_VERSION && ${MIN_OSX_VERSION-_} ]]; then
 fi
 
 CFLAGS="$CFLAGS $C_FLAGS -fvisibility=hidden"
-CXXFLAGS="$CXXFLAGS $C_FLAGS -stdlib=libc++ -std=c++14 -msse4.1"
+CXXFLAGS="$CXXFLAGS $C_FLAGS -stdlib=libc++ -std=c++17 -msse4.1"
 OBJCFLAGS="$OBJCFLAGS $C_FLAGS"
 OBJCXXFLAGS="$OBJCXXFLAGS $C_FLAGS"
 
@@ -427,6 +427,7 @@ then
     --without-libtiff
     --without-sdl
     --without-x
+    --disable-stc
     --disable-webview
     --disable-webkit
     --disable-webviewwebkit