[libc] Move struct timespec from POSIX to StdC (#85010)

`struct timespec` is actually defined in the C standard, not POSIX.

Author: petrhosek

libc/spec/posix.td

@@ -42,10 +42,6 @@ def StructDirentPtr : PtrType<StructDirent>;
 def StructDirentPtrPtr : PtrType<StructDirentPtr>;
 def ConstStructDirentPtrPtr : ConstType<StructDirentPtrPtr>;
 
-def StructTimeSpec : NamedType<"struct timespec">;
-def StructTimeSpecPtr : PtrType<StructTimeSpec>;
-def ConstStructTimeSpecPtr : ConstType<StructTimeSpecPtr>;
-
 def StructSchedParam : NamedType<"struct sched_param">;
 def StructSchedParamPtr : PtrType<StructSchedParam>;
 def ConstStructSchedParamPtr : ConstType<StructSchedParamPtr>;

libc/spec/spec.td

@@ -118,6 +118,10 @@ def SigHandlerT : NamedType<"__sighandler_t">;
 
 def TimeTType : NamedType<"time_t">;
 
+def StructTimeSpec : NamedType<"struct timespec">;
+def StructTimeSpecPtr : PtrType<StructTimeSpec>;
+def ConstStructTimeSpecPtr : ConstType<StructTimeSpecPtr>;
+
 def BSearchCompareT : NamedType<"__bsearchcompare_t">;
 def QSortCompareT : NamedType<"__qsortcompare_t">;
 

libc/spec/stdc.td

@@ -1202,6 +1202,7 @@ def StdC : StandardSpec<"stdc"> {
       [ // Types
          ClockT,
          StructTmType,
+         StructTimeSpec,
          TimeTType,
       ],
       [], // Enumerations