Replace all calls to sigprocmask() in the OS proper with calls to nxsig_procmask().
sched/signal: Add internal OS interface nxsig_procmask(). This internal interface is equivalent to the standard sigprocmask() used by applications except that it does not modify the errno value. Also fixes a problem in that the original sigprocmask() was not setting the errno.
binfmt: Fix some compilation issues introduced in previous changes. Verfied with the STM32F4-Discovery ELF configuration.
binfmt: schedule_unload() is an internal OS function and must not alter the errno variable.
binfmt: unload_module() is an internal OS function and must not alter the errno variable.
binfmt: load_module() is an internal OS function and must not alter the errno variable.
binfmt: exec_module() is an internal OS function and must not alter the errno variable.
