Cygwin: rand(3): implement in terms of random(3)

This makes rand(3) ISO C compliant and adds locking to avoid
race conditions.

Reported-by: Bruno Haible <bruno@clisp.org>
Fixes: 8a0efa53e4 ("import newlib-2000-02-17 snapshot")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/random.cc

@@ -293,6 +293,8 @@ srandom(unsigned x)
 	__random_unlock();
 }
 
+EXPORT_ALIAS (srandom, srand)
+
 /*
  * initstate:
  *
@@ -481,4 +483,10 @@ random()
 	return (r);
 }
 
+int
+rand()
+{
+	return ((int) random());
+}
+
 }

winsup/cygwin/release/3.4.10

@@ -15,3 +15,6 @@ Bug Fixes
 
 - Updates to profiler and gmondump: error display mechanics, buffer sizing,
   and output formatting.
+
+- Align behaviour of rand(3) to ISO C.
+  Adresses: https://cygwin.com/pipermail/cygwin/2023-November/254735.html