[tlbuild] tl18 trials

[Arthur Reutenauer]

> #ifdef __linux__
> #define _GNU_SOURCE _glibc_developers_are_idiots_to_call_strndup_gnu_specific_
> #endif

  :-)

  This seems to be a work around this recommendation from the man page:

	Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

	strndup():
	   Since glibc 2.10:
	       _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700
	   Before glibc 2.10:
	       _GNU_SOURCE

	Best,

		Arthur