Even when configure detects a working system regex, or --without-included-regex is used,
#include "regex.h" (which is what gnulib tells you to use) uses the included regex.h, not the system one. There are obvious potential problems with this: if the ABI changes you could end up with a header that doesn't match the linked code, and even without that you can end up thinking you have features (e.g. syntax bits) which are not in fact available in the code. -- http://rrt.sc3d.org
