diff --git a/components/multithreadprocs/mtpcpu.pas b/components/multithreadprocs/mtpcpu.pas
index 79cf6562ea..3337b859e2 100644
--- a/components/multithreadprocs/mtpcpu.pas
+++ b/components/multithreadprocs/mtpcpu.pas
@@ -68,6 +68,8 @@ end;
     t = sysconf(_SC_NPROC_ONLN);
   end;
 {$ELSEIF defined(freebsd) or defined(darwin)}
+type
+  PSysCtl = {$IF FPC_FULLVERSION>30300}pcint{$ELSE}pchar{$ENDIF};
 var
   mib: array[0..1] of cint;
   len: csize_t;
@@ -76,7 +78,7 @@ begin
   mib[0] := CTL_HW;
   mib[1] := HW_NCPU;
   len := sizeof(t);
-  fpsysctl(pchar(@mib), 2, @t, @len, Nil, 0);
+  fpsysctl(PSysCtl(@mib), 2, @t, @len, Nil, 0);
   Result:=t;
 end;
 {$ELSEIF defined(linux)}