thread: Avoid compiler warnings on Solaris

[Bruno Haible]

On Solaris 11, I see many warnings:
gllib/glthread/thread.h:236:27: warning: cast to pointer from integer of 
different size [-Wint-to-pointer-cast]
I wouldn't care much about 1 warning, but these are many.

This patch fixes them.


2023-06-25  Bruno Haible  <bruno@clisp.org>

        thread: Avoid compiler warnings on Solaris.
        * lib/glthread/thread.h: Include <stdint.h>.
        (gl_thread_self_pointer): Do the cast from pthread_t to 'void *' via
        intptr_t.
        * modules/thread (Depends-on): Add stdint.

diff --git a/lib/glthread/thread.h b/lib/glthread/thread.h
index 88bc53ee7f..942ce70b5c 100644
--- a/lib/glthread/thread.h
+++ b/lib/glthread/thread.h
@@ -130,6 +130,9 @@ extern _Noreturn void gl_thread_exit (void *return_value);
 
 # include <pthread.h>
 
+/* Get intptr_t.  */
+# include <stdint.h>
+
 /* On IRIX, pthread_atfork is declared in <unistd.h>, not in <pthread.h>.  */
 # if defined __sgi
 #  include <unistd.h>
@@ -233,7 +236,7 @@ extern const gl_thread_t gl_null_thread;
 #  define gl_thread_self() \
      (pthread_in_use () ? pthread_self () : (pthread_t) 0)
 #  define gl_thread_self_pointer() \
-     (pthread_in_use () ? (void *) (pthread_t) pthread_self () : NULL)
+     (pthread_in_use () ? (void *) (intptr_t) (pthread_t) pthread_self () : 
NULL)
 # endif
 # define gl_thread_exit(RETVAL) \
     (void) (pthread_in_use () ? (pthread_exit (RETVAL), 0) : 0)
diff --git a/modules/thread b/modules/thread
index 1d530b0d3a..f416807b63 100644
--- a/modules/thread
+++ b/modules/thread
@@ -8,6 +8,7 @@ m4/thread.m4
 
 Depends-on:
 threadlib
+stdint
 extern-inline
 lock
 windows-thread  [test $gl_threads_api = windows]