make error php 4.3.4 apache 2: sapi/apache2handler/sapi_apache2.lo Error 1

I have already this combination of php and apache2 running for a while, but because of other reasons I now have to compile php again. After ./configure and make clean and make I now get the following errors, and I have no idea why. I searched google and php sites for information, but cant find a solution. It has worked before... /bin/sh /root/php-4.3.4/libtool --silent --preserve-dup-deps --mode=compile gcc -I/usr/local/apache2/include -I/usr/local/apache2/include -I/usr/local/apache2/include -Isapi/apache2handler/ -I/root/php-4.3.4/sapi/apache2handler/ -DPHP_ATOM_INC -I/root/php-4.3.4/include -I/root/php-4.3.4/main -I/root/php-4.3.4 -I/root/php-4.3.4/Zend -I/usr/local/include -I/usr/local/mysql/include -I/root/php-4.3.4/ext/xml/expat -I/root/php-4.3.4/TSRM -g -O2 -prefer-pic -c /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c -o sapi/apache2handler/sapi_apache2.lo /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:38: apr_strings.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:39: ap_config.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:40: util_filter.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:41: httpd.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:42: http_config.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:43: http_request.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:44: http_core.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:45: http_protocol.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:46: http_log.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:47: http_main.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:48: util_script.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:49: http_core.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:50: ap_mpm.h: No such file or directory In file included from /root/php-4.3.4/sapi/apache2handler/sapi_apache2.c:52: /root/php-4.3.4/sapi/apache2handler/php_apache.h:24: httpd.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/php_apache.h:25: http_config.h: No such file or directory /root/php-4.3.4/sapi/apache2handler/php_apache.h:26: http_core.h: No such file or directory make: *** [sapi/apache2handler/sapi_apache2.lo] Error 1