Remove workaround for bug in Xcode, m4 is included again in version 16

This reverts commit 54956c22.

macOS/build.sh

@@ -40,11 +40,6 @@ else
 fi
 MATLAB_PATH=/Applications/"$PKG_ARCH"/MATLAB_R2024b.app
 
-# Workaround for bug in Xcode 15.3 which does not include m4
-# See https://github.com/Homebrew/homebrew-core/issues/165388
-# and https://trac.macports.org/ticket/69639
-path_prepend PATH "$BREWDIR"/opt/m4/bin
-
 # Append texbin to PATH to access latexmk and friends
 path_prepend PATH /Library/TeX/texbin