Fix `XDeclaredButNotUsed` warning when locks or rlocks module is used

lib/core/locks.nim

@@ -63,4 +63,4 @@ template withLock*(a: Lock, body: untyped) =
     try:
       body
     finally:
-      a.release()
+      a.release()

lib/core/rlocks.nim

@@ -9,6 +9,7 @@
 
 ## This module contains Nim's support for reentrant locks.
 
+const insideRLocksModule = true
 include "system/syslocks"
 
 type

lib/system.nim

@@ -2561,6 +2561,16 @@ else:
     if x < 0: -x else: x
 {.pop.}
 
+proc compiles*(x: expr): bool {.magic: "Compiles", noSideEffect, compileTime.} =
+  ## Special compile-time procedure that checks whether `x` can be compiled
+  ## without any semantic error.
+  ## This can be used to check whether a type supports some operation:
+  ##
+  ## .. code-block:: Nim
+  ##   when not compiles(3 + 4):
+  ##     echo "'+' for integers is available"
+  discard
+
 when not defined(JS): #and not defined(nimscript):
   {.push stack_trace: off, profiler:off.}
 
@@ -3469,16 +3479,6 @@ when hasAlloc:
       x[j+i] = item[j]
       inc(j)
 
-proc compiles*(x: expr): bool {.magic: "Compiles", noSideEffect, compileTime.} =
-  ## Special compile-time procedure that checks whether `x` can be compiled
-  ## without any semantic error.
-  ## This can be used to check whether a type supports some operation:
-  ##
-  ## .. code-block:: Nim
-  ##   when not compiles(3 + 4):
-  ##     echo "'+' for integers is available"
-  discard
-
 when declared(initDebugger):
   initDebugger()
 

lib/system/syslocks.nim

@@ -88,17 +88,16 @@ else:
                           #include <pthread.h>""".} = object
     SysLockType = distinct cint
 
-  proc SysLockType_Reentrant: SysLockType =
-    {.emit: "`result` = PTHREAD_MUTEX_RECURSIVE;".}
-
   proc initSysLock(L: var SysLock, attr: ptr SysLockAttr = nil) {.
     importc: "pthread_mutex_init", header: "<pthread.h>", noSideEffect.}
 
-  proc initSysLockAttr(a: var SysLockAttr) {.
-    importc: "pthread_mutexattr_init", header: "<pthread.h>", noSideEffect.}
-
-  proc setSysLockType(a: var SysLockAttr, t: SysLockType) {.
-    importc: "pthread_mutexattr_settype", header: "<pthread.h>", noSideEffect.}
+  when compiles(insideRLocksModule):
+    proc SysLockType_Reentrant: SysLockType =
+      {.emit: "`result` = PTHREAD_MUTEX_RECURSIVE;".}
+    proc initSysLockAttr(a: var SysLockAttr) {.
+      importc: "pthread_mutexattr_init", header: "<pthread.h>", noSideEffect.}
+    proc setSysLockType(a: var SysLockAttr, t: SysLockType) {.
+      importc: "pthread_mutexattr_settype", header: "<pthread.h>", noSideEffect.}
 
   proc acquireSys(L: var SysLock) {.noSideEffect,
     importc: "pthread_mutex_lock", header: "<pthread.h>".}
@@ -113,14 +112,12 @@ else:
   proc deinitSys(L: var SysLock) {.noSideEffect,
     importc: "pthread_mutex_destroy", header: "<pthread.h>".}
 
-  proc initSysCond(cond: var SysCond, cond_attr: pointer = nil) {.
-    importc: "pthread_cond_init", header: "<pthread.h>", noSideEffect.}
-  proc waitSysCond(cond: var SysCond, lock: var SysLock) {.
-    importc: "pthread_cond_wait", header: "<pthread.h>", noSideEffect.}
-  proc signalSysCond(cond: var SysCond) {.
-    importc: "pthread_cond_signal", header: "<pthread.h>", noSideEffect.}
-
-  proc deinitSysCond(cond: var SysCond) {.noSideEffect,
-    importc: "pthread_cond_destroy", header: "<pthread.h>".}
-
-{.pop.}
+  when not compiles(insideRLocksModule):
+    proc initSysCond(cond: var SysCond, cond_attr: pointer = nil) {.
+      importc: "pthread_cond_init", header: "<pthread.h>", noSideEffect.}
+    proc waitSysCond(cond: var SysCond, lock: var SysLock) {.
+      importc: "pthread_cond_wait", header: "<pthread.h>", noSideEffect.}
+    proc signalSysCond(cond: var SysCond) {.
+      importc: "pthread_cond_signal", header: "<pthread.h>", noSideEffect.}
+    proc deinitSysCond(cond: var SysCond) {.noSideEffect,
+      importc: "pthread_cond_destroy", header: "<pthread.h>".}