Fix some compilation errors on POSIX linux.

core/sys/posix/sys_times.odin

@@ -24,7 +24,7 @@ when ODIN_OS == .NetBSD {
 	@(private) LTIMES :: "times"
 }
 
-when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD {
+when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD || ODIN_OS == .Linux {
 
 	tms :: struct {
 		tms_utime:  clock_t, /* [PSX] user CPU time */

core/sys/posix/sys_uio.odin

@@ -30,7 +30,7 @@ foreign libc {
 	writev :: proc(fildes: FD, iov: [^]iovec, iovcnt: c.int) -> c.ssize_t ---
 }
 
-when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD {
+when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD || ODIN_OS == .Linux {
 
 	iovec :: struct {
 		iov_base: rawptr,   /* [PSX] base address of I/O memory region */

core/sys/posix/sys_un.odin

@@ -12,6 +12,13 @@ when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS
 		sun_path:   [104]c.char, /* [PSX] socket pathname */
 	}
 
+} else when ODIN_OS == .Linux {
+
+	sockaddr_un :: struct {
+		sun_family: sa_family_t, /* [PSX] address family */
+		sun_path:   [108]c.char, /* [PSX] socket pathname */
+	}
+
 } else {
 	#panic("posix is unimplemented for the current target")
 }

core/sys/posix/ulimit.odin

@@ -31,7 +31,7 @@ Ulimit_Cmd :: enum c.int {
 	SETFSIZE = UL_SETFSIZE,
 }
 
-when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD {
+when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD  || ODIN_OS == .Linux {
 
 	UL_GETFSIZE :: 1
 	UL_SETFSIZE :: 2

core/sys/posix/utime.odin

@@ -24,7 +24,7 @@ when ODIN_OS == .NetBSD {
 	@(private) LUTIME :: "utime"
 }
 
-when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD	{
+when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD	|| ODIN_OS == .Linux {
 
 	utimbuf :: struct {
 		actime:  time_t, /* [PSX] access time (seconds since epoch) */