What is the __libc_enable_secure call used for and is it possible to do without it?

Question

GCC

I am compiling RPM p11-kit version 0.23.2 under CentOS 6 from SRPM according to the spec taken from the package of version 0.20.7 from CentOS 7. I did not make any changes to the spec, except for the version number and removing the already unnecessary patch. Building without problems, but when trying to install the built RPM, this message appears:
Error: Package: p11-kit-0.23.2-4.el6.x86_64 (/p11-kit-0.23.2-4.el6.x86_64)
Requires: ld-linux-x86-64.so.2(GLIBC_PRIVATE)(64bit) See
what causes this dependency:

# objdump -t libp11-kit.so.0.1.0 | grep PRIVATE
0000000000000000 O *UND* 000000000000000 [email protected]@GLIBC_PRIVATE
In configure.ac I find this:

AC_LINK_IFELSE([AC_LANG_PROGRAM(, , )],
[AC_DEFINE(HAVE___LIBC_ENABLE_SECURE, [1], [Whether __libc_enable_secure available])])
This line does not exist in version 0.18.5, it appears since 0.20. The question is why this call is needed and what can I lose if I remove these lines from configure.ac (then the dependency disappears)