Missing syscalls/library calls

[danielinux]

• [x] vfork
• [x] sigaction
• [x] sigisemptyset
• [x] sigprocmask
• [x] sigsuspend
• [x] fnmatch
• [x] tcgetattr
• [x] getrlimit
• [x] setrlimit
• [x] umask
• [x] pipe
• [x] _malloc_trim_r

[maximevince]

fnmatch will indeed be provided by newlib

[danielinux]

Implementation done. Test in progress...