Officially since C11 (and in reality FreeBSD since 3.0 with commit
1b46cb523d) errno has been defined to be a macro. Rename the symbol
to __libsys_errno and move it to FBSDprivate_1.0 and confine it entierly
to libsys for use by libthr. Add a FBSD_1.0 compat symbol for existing
binaries that were incorrectly linked to the errno symbol during
libc.so.7's lifetime.
This deliberately breaks linking software that directly links to errno.
Such software is broken and will fail in surprising ways if it becomes
threaded (e.g., if it triggers loading of a pam or nss module that
uses threads.)
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D46780
Before, the 'errno' itself was defined in libc and was referenced by
libsys, causing undesired dependency.
Reviewed by: brooks, imp
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D43985
Remove core system call implementations and documentation to lib/libsys
and lib/libsys/<arch> from lib/libc/sys and lib/libc/<arch>/<sys>.
Update paths to allow libc to find them in their new home.
Reviewed by: kib, emaste, imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/908
