On a build I am getting this error:

gcc -DHAVE_CONFIG_H -I. -I/home/root/src/apache_ssl/php-4.0.1pl2/main -I/home/root/src/apache_ssl/php-4.0.1pl2 -I/home/root/src/apache_ssl/php-4.0.1pl2/main -I/home/root/src/apache_ssl/php-4.0.1pl2/Zend -I/home/root/src/apache_ssl/php-4.0.1pl2 -I/usr/include/freetype -I/usr/include/gd -I/home/root/src/apache_ssl/php-4.0.1pl2/ext/mysql/libmysql -I/home/root/src/apache_ssl/php-4.0.1pl2/ext/xml/expat/xmltok -I/home/root/src/apache_ssl/php-4.0.1pl2/ext/xml/expat/xmlparse  -DXML_BYTE_ORDER=21 -g -O2  -c main.c && touch main.lo
main.c: In function `php_error_cb':
main.c:370: incompatible types in assignment
main.c:435: incompatible types in assignment

I got around it by commenting out the va_list arg; defines and changing the arguments to php_error_cb to use args directly on lines 370 & 435:

static void php_error_cb(int type, const char *error_filename, const uint error_lineno, const char *format, va_list args)
[...]
//args = orig_args;

This appears to still compile and passes my basic testing. Although I am sure something is going to bite me on this style of patch.