Update gnulib to stable-202301

[sidsbrmnn]

This pull request is to update Gnulib to its latest stable upstream, stable-202301. The currently used snapshot of Gnulib is as old as February 9, 2016 and gnulib has undergone plenty of improvements and security fixes on vulnerabilities. Amanda maintains a snapshot of Gnulib with its code to maintain portability and consistency across Unix-like platforms where the GNU C Library is not the default C Library.

Changes Made

• config/gnulib: updated *.m4 macros for Gnulib (written by gnulib-tool command)
• gnulib: updated Gnulib (written by gnulib-tool command)
• gnulib/regenerate/regenerate: updated script with the commit hash of the Gnulib snapshot used and cleaned up the script for readability
• config/amanda/socklen_t_equiv.m4: updated checks for sys/socket.h header file using the newer gl_SYS_SOCKET_H macro
• configure.ac: added default value to GNULIBHEADERS_OVERRIDE_WINT_T as it is left undefined due to a macro override by gettext

Testing Done

I've currently tested the builds on CentOS 7, Rocky Linux 9 and Fedora 37.

[chandraravipati]

@sidsbrmnn please add more detailed description explaining the need for these changes and the changes.

[sidsbrmnn]

@sidsbrmnn please add more detailed description explaining the need for these changes and the changes.

I've updated the description with the details.