Install Xcode For Mac Catalina

After figuring out a way around the massive breaking change introduced by Xcode 11, it's now time to install Xdebug back on MacOS Catalina.

Update from January 6th 2021:
Using MacOS Big Sur? This solution should work for you too. But since Apple Deprecated PHP in MacOS Big Sur, you should probably rely on Homebrew now.

Before we get right to how to install command line tools on macOS, let us look at what macOS Catalina is all about. Apple just made available a major release of its macOS codenamed macOS Catalina (version 10.15). MacOS Catalina is the sixteenth release of Apple’s desktop operating system for Macintosh computers.
Alternatively, if you are a MAC user is to install MAMP. It comes with the xdebug extension ready to use in all the versions of php that MAMP has built-in. After installing MAMP, you just have to add these lines in the php.ini file corresponding to each version of PHP: For php8.
Users who don’t have Xcode can install it with a single command: xcode-select -install. With Xcode running on your Mac, you can check whether Git is also available by prompting for the Git version: git -version. The output should display the latest Git release, as in the example below. Git version 2.25.0 (Apple Git-66).

Update from June 30th 2020:
After some new investigation while trying to upgrade to a newer version of xdebug, I now believe most of the instructions in this post are not necessary. Before doing anything, you should check if xdebug.so already exists in /usr/lib/php/extensions/no-debug-non-zts-20180731/, which I believe is there by default (let me know if otherwise). If it does exist, you could skip to the Enabled support in PHP portion of this post.

Install XCode on macOS Catalina 10.15 on Windows PC When you installed macOS Catalina 10.15 on Virtual machine. Then Power on the virtual machine. When you entered the macOS Catalina window click on the Apple Mac App Store.

Note that building xdebug from source code and actually trying to use that version of xdebug.so (for example by referencing the built file in xdebug/module/xdebug.so after using make install) with the build-in PHP should end up in a 'code signature' error. As described here and here, even after signing the binary, MacOS won't allow system binaries to interact with non-system binaries for security reasons. The only real solution to use a custom version of xdebug would be to compile and use you own instance of PHP instead of the build in one.

Long story short, Apple decided to nuke /usr/include in MacOS Catalina, which has been the default location for C header file for ever in UNIX systems. Trying to install through PEAR / PECL will return an error as the compiler will look for necessary headers file in /usr/include. So the solution is to compile Xdebug manually, manually specifying the actual location of the header files, which are still provided by Xcode, just at a different location.

Xcode

The first step is to get Xcode from the App Store.

Once Xcode installed, we have to get the command line tools :

You might need to actually open Xcode at this point to finish installation and accept terms and conditions, especially if the previous command fails.

Finally, make sure the SDK is found. If the path you get differs from the one bellow, you might need to edit the path accordingly later on:

Manually Compiling Xdebug

Getting source

Let's compile 2.7.2, getting the source code from git. Alternatively, you can download the source from Xdebug site.

phpize

Next we need to make a copy phpize so we can edit the include path :

Find this line :

...and replace it with this line :

Run phpize:

You should now see something like this :

Configure & build

We can now configure :

...and run make using our custom SDK location defined as compiler flags. I used a variable to store the path to the SDK so it's easier to edit if it changes :

You might see some warning, just ignore it for now. Finally, we'll need to run :

Again, this command will fail because it can't move the extension to the right place. SIP will prevent it. But no worries, we'll take care of that manually at the next step. make install is still required as it will sign the *.so file.