I'm not sure if this is a characteristic of Mac xampp, or all the xampp distro's, but it's just something I came across. When I tried to compile the Xdebug extension, I ran into a couple of problems. First, when I ran phpize, it reported:
PHP Api Version: 20020918
Zend Module Api No: 20020429
Zend Extension Api No: 20050606
Which is the php4 versions. I have my apache switched to load php5, but apparently my cli binaries (php, phpize, php-config in /usr/local/bin) remained php4. I don't know if xampp did that or not, but I deleted those and updated my path to include /Applications/xampp/xamppfiles/bin so that my command-line executables would come from the sym-links in there. After that, my phpize reported the right versions:
PHP Api Version: 20041225
Zend Module Api No: 20060613
Zend Extension Api No: 220060519
Second, when I tried to make in the xdebug-2.0.0RC3 folder, I got:
In file included from /Applications/xampp/xamppfiles/include/php/php5/php/main/php.h:34,
/Applications/xampp/xamppfiles/include/php/php5/php/Zend/zend.h:72:19: error: unix.h: No such file or directory
make: *** [xdebug.lo] Error 1
The unix.h file is located in /Applications/xampp/xamppfiles/include
I updated the Makefile to include -I/Applications/xampp/xamppfiles/include in front of the other include dirs and the compile worked.
While investigating I noticed my php-config script contained the following:
includes="-I$includedir -I$includedir/main -I$includedir/TSRM -I$includedir/Zend -I$includedir/ext -I$includedir/ext/date/lib"
Should it also include the /Applications/xampp/xamppfiles/include entry?
Anyway, just some thoughts for consideration.