I keep getting this error when building on Mountain Lion using Apportable. How do I fix it ? or stop this appearing ?
The M4 error is caused when you are missing the Xcode Command Line tools.
Go to Xcode->Preferences->Downloads->Command Line Tools and click the install button.
Subsequent apportable builds will then find the m4 command properly.
The next SDK update (R11) will automatically address this by including an M4 and not relying upon the Xcode installation.