Fix Missing Headers Compiling on macOS Mojave
While trying to compile PHP extensions after installing macOS Mojave, I was butting up against a ton of missing header file errors including
php.h and zlib.
After several hours of beating my head against my desk and Googling/Stack Overflowing I found the solution.
Ends up you just need to force re-install the header files. Special thanks to @sfdye for the solution!
$ sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /
If you get an error about that file not existing, you probably simply don't have the Xcode command line tools installed which can be remedied simply as follows:
$ xcode-select --install