osxcross cannot find libc++ headers

[LinuxUserGD]

Godot version:
master

OS/device including version:
Antergos OS (Arch Linux)

Issue description:
Don't know if it should better report it on the OSXCross repo or here.
Can't compile Godot for OSX on Linux using the package apple-darwin-osxcross, because it can't find the libc++ headers that are located at /opt/osxcross/SDK/MacOSX10.11.sdk/usr/include/c++/4.2.1 and /opt/osxcross/x86_64-apple-darwin15/include/c++/7.1.1.

I've tried symbolic links using
ln -s /opt/osxcross/bin /opt/osxcross/target (successful) ,
sudo ln -s /opt/osxcross/SDK/MacOSX10.11.sdk/usr/include/c++/4.2.1 /opt/osxcross/x86_64-apple-darwin15/include/c++ and
sudo ln -s /opt/osxcross/x86_64-apple-darwin15/include/c++/7.1.1 /opt/osxcross/SDK/MacOSX10.11.sdk/usr/include/c++ without success.

Steps to reproduce:

yaourt -S apple-darwin-osxcross
sudo ln -s /opt/osxcross/bin /opt/osxcross/target
export OSXCROSS_ROOT=/opt/osxcross
scons p=osx osxcross_sdk=darwin15

Error Output:

scons: Reading SConscript files ...
Checking for C header file mntent.h... (cached) no
scons: done reading SConscript files.
scons: Building targets ...
[  2%] Compiling ==> platform/osx/crash_handler_osx.mm
osxcross: error: cannot find libc++ headers
osxcross: error: while detecting target
scons: *** [platform/osx/crash_handler_osx.osx.tools.64.o] Error 1
scons: building terminated because of errors.
[user@user godot]$ 

[LinuxUserGD]

Building osxcross manually from source works:

• git clone https://github.com/tpoechtrager/osxcross.git
• download Xcode 7.3.1 from https://developer.apple.com/downloads/index.action?name=Xcode%207.3
• run https://github.com/tpoechtrager/osxcross/blob/master/tools/gen_sdk_package.sh (which clones, compiles and runs https://github.com/darlinghq/darling-dmg, extracts Xcode_7.3.1.dmg as MacOSX10.11.sdk)
• run https://github.com/tpoechtrager/osxcross/blob/master/build_gcc.sh

export OSXCROSS_ROOT=/run/media/user/user/git/osxcross
scons p=osx osxcross_sdk=darwin15 tools=no target=release -j 8
scons p=osx osxcross_sdk=darwin15 tools=no target=release_debug -j 8

Maybe the AUR package apple-darwin-osxcross creates the components in different directories, so it didn't work.