5 POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/log2l.html}
9 Portability problems fixed by Gnulib:
12 This function is missing on some platforms:
13 FreeBSD 6.0, NetBSD 9.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, older IRIX 6.5, Solaris 9, Cygwin 1.7.x, MSVC 9, Android 4.2.
15 This function is not declared on some platforms:
19 Portability problems not fixed by Gnulib: