Make RUsage more inline with macos man page

Swap to tabs to adhere to the Odin Core library standard
and also rename the rusage fields to match the actual
definitions from the macos bsd man pages

core/sys/darwin/darwin.odin

@@ -3,26 +3,27 @@ package darwin
 
 Bool :: b8
 
-timespec :: struct {
-        seconds:      int,
-        microseconds: int,
+timeval :: struct {
+	tv_sec:  int,
+	tv_usec: int,
 }
 
 RUsage :: struct {
-        utime:         timespec,
-        stime:         timespec,
-        maxrss_word:   int,
-        ixrss_word:    int,
-        idrss_word:    int,
-        isrss_word:    int,
-        minflt_word:   int,
-        majflt_word:   int,
-        nswap_word:    int,
-        inblock_word:  int,
-        oublock_word:  int,
-        msgsnd_word:   int,
-        msgrcv_word:   int,
-        nsignals_word: int,
-        nvcsw_word:    int,
-        nivcsw_word:   int,
+	ru_utime:    timeval,
+	ru_stime:    timeval,
+	ru_maxrss:   int,
+	ru_ixrss:    int,
+	ru_idrss:    int,
+	ru_isrss:    int,
+	ru_minflt:   int,
+	ru_majflt:   int,
+	ru_nswap:    int,
+	ru_inblock:  int,
+	ru_oublock:  int,
+	ru_msgsnd:   int,
+	ru_msgrcv:   int,
+	ru_nsignals: int,
+	ru_nvcsw:    int,
+	ru_nivcsw:   int,
 }
+