Error when building 5.6.0-alpha from source on Mac

[MarcVanDaele]

I tried to build 5.6.0-alpha on Mac (never built Qt from sources before)
So I downloaded the sources, called ./configure and make
After about 4 hours, make ended with the following errors.
Advice on how to proceed is much appreciated (please let me know if you need more information)

clang: error: no such file or directory: '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/lib/libbsm.dylib'
clang: error: no such file or directory: '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/lib/libresolv.dylib'
clang: error: no such file or directory: '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/lib/libz.dylib'
clang: error: no such file or directory: '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/lib/libcups.dylib'
make[5]: *** [../../lib/QtWebEngineCore.framework/QtWebEngineCore_debug] Error 1
make[4]: *** [debug-install] Error 2
make[3]: *** [sub-core_module-pro-install_subtargets] Error 2
make[2]: *** [sub-core-install_subtargets] Error 2
make[1]: *** [sub-src-install_subtargets] Error 2
make: *** [module-qtwebengine-install_subtargets] Error 2

[jsulm]

Did you check whether you have the right SDK installed (10.11)?
Does the path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk exist?

To reduce the time needed to build Qt you can call make like this:
make -j N
Where N = NUMBER_OF_CPU_CORES + 1