fix int32's that should be uint32 on BSD & OSX (#24078)

fixes #24076

As described in #24076, misannotating these types causes codegen errors.
Sources for the types are https://github.com/openbsd/src/blob/master/sys
for BSD and https://opensource.apple.com/source/Libinfo/Libinfo-391/ and
[_types.h](https://opensource.apple.com/source/xnu/xnu-1456.1.26/bsd/sys/_types.h.auto.html)
for OSX.

(cherry picked from commit 7de4ace949)

tests/stdlib/twronguidtype.nim

@@ -0,0 +1,8 @@
+# issue #24076
+
+when defined(macosx) or defined(freebsd) or defined(openbsd) or defined(netbsd):
+  import std/posix
+  proc uid(x: uint32): Uid = Uid(x)
+  var y: uint32
+  let myUid = geteuid()
+  discard myUid == uid(y)