Locks modules should give a compile error when threads are not enabled. (#12231)

* Locks modules should give a compile error when threads are not enabled.

* fix the compile flags to make the tests pass, or ignore files where necessary.

* Fixed when statement to account for doc builds.

lib/core/rlocks.nim

@@ -9,6 +9,10 @@
 
 ## This module contains Nim's support for reentrant locks.
 
+
+when not compileOption("threads") and not defined(nimdoc):
+  {.error: "Rlocks requires --threads:on option.".}
+
 const insideRLocksModule = true
 include "system/syslocks"