xcode - macOS 'wchar.h' File Not Found

Question

Under OS X 10.9.5 using XCode 6.0.1 I am running into the following issue when I try to run make from the terminal:

fatal error: 'wchar.h' file not found

This issue was not happening prior to a recent upgrade to Mavericks.

Answer 1

First ensure that the latest XCode is installed. Next, we need to install/fix/update Command Line Tools. To do so, run

xcode-select --install

Previously, XCode expected it's active developer directory to be located at

/Applications/Xcode.app/Contents/Developer/

but the latest Command Line Tools is installed to

/Library/Developer/CommandLineTools/

so we need to switch where XCode is looking. To do so, run

sudo xcode-select --switch /Library/Developer/CommandLineTools/

And that should be it. These steps solved the issue for myself and two coworkers.