Add missing network declaration for Solaris.

These are required to compile std.socket.
(cherry picked from commit 7a16090551acb81a5b0e5a173e3d9280718378d5)
Add more Solaris declarations.

Add missing declations in `core.sys.posix.utime` and `core.sys.posix.utime`.
(cherry picked from commit 8317b7758a2d2ef85280e71ae51172c94116d13c)
Fix typo in core.sys.posix.grp

The thread-safe function to get the group is is named getgrgid_r and not getgruid_r.
(cherry picked from commit 3c9690dfa6be312354461dd59cffddd310509a89)