Extending and Embedding PHP and php 5.1.0 - php

Question

I am currently reading a book: Extending and Embedding PHP.
I have Ubuntu 16 . The book wants:
./configure <--- worked.
But with "make all install" I get a error message:
movic/Downloads/php-5.1.0/ext/dom/documenttype.c -o ext/dom/documenttype.lo
/home/tomovic/Downloads/php-5.1.0/meta_ccld -Iext/dom/ -I/home/tomovic/Downloads/php-5.1.0/ext/dom/ -DPHP_ATOM_INC -I/home/tomovic/Downloads/php-5.1.0/include -I/home/tomovic/Downloads/php-5.1.0/main -I/home/tomovic/Downloads/php-5.1.0 -I/usr/include/libxml2 -I/home/tomovic/Downloads/php-5.1.0/ext/date/lib -I/home/tomovic/Downloads/php-5.1.0/TSRM -I/home/tomovic/Downloads/php-5.1.0/Zend -D_REENTRANT -g -O2 -pthread -Wall -DZTS -c /home/tomovic/Downloads/php-5.1.0/ext/dom/documenttype.c -fPIC -DPIC -o ext/dom/.libs/documenttype.o
/home/tomovic/Downloads/php-5.1.0/ext/dom/documenttype.c: In function 'dom_documenttype_internal_subset_read':
/home/tomovic/Downloads/php-5.1.0/ext/dom/documenttype.c:219:42: error: dereferencing pointer to incomplete type 'xmlBuf {aka struct _xmlBuf}'
strintsubset = xmlStrndup(buff->buffer->content, buff->buffer->use);
^
Makefile:408: die Regel für Ziel „ext/dom/documenttype.lo“ scheiterte
make: *** [ext/dom/documenttype.lo] Fehler 1
root#DELL:~/Downloads/php-5.1.0#

Answer 1

Throw that book out and find another one.
PHP 5.1 is completely obsolete -- it was released in 2005, and has not been supported since the release of PHP 5.2 in November 2006. Due to changes in various libraries, it can no longer be compiled on modern Linux systems. Moreover, PHP has gone through a number of internal changes over the last 12 years, and much of the advice in that book is likely to be inaccurate today.
For an up-to-date look at PHP internals, refer to the PHP at the Core: A Hacker's Guide section of the PHP manual.