Implement lifetime support for thread pools

tests/thread-pool.scm

@@ -85,4 +85,26 @@
              (+ 1 'a))))
         #:unwind? #t)))))
 
+(let ((thread-pool
+       (make-fixed-size-thread-pool 1 #:thread-lifetime 1)))
+
+  (for-each
+   (lambda _
+     (call-with-thread
+      thread-pool
+      (lambda () #f)))
+   (iota 10)))
+
+(run-fibers-for-tests
+ (lambda ()
+   (let ((thread-pool
+          (make-thread-pool 1 #:thread-lifetime 1)))
+
+     (for-each
+      (lambda _
+        (call-with-thread
+         thread-pool
+         (lambda () #f)))
+      (iota 10)))))
+
 (display "thread-pool test finished successfully\n")