thread: Fix test link error on DragonFly BSD 6.0

[Bruno Haible]

On DragonFly BSD 6.0, when compiling a testdir with CFLAGS=-g (no gcc
optimizations), I get a link error:

gcc  -ggdb   -o test-thread_self test-thread_self.o libtests.a 
../gllib/libgnu.a libtests.a ../gllib/libgnu.a libtests.a  -lm -lm -lm -lm -lm 
-lm -lm -lm -lm -lm -lm
../../gltests/../gllib/glthread/thread.h:323: error: undefined reference to 
'pthread_create'
collect2: error: ld returned 1 exit status
*** Error code 1 (continuing)

The reason is that glthread/thread.h contains a supposedly inline function
'gl_thread_create'. But on this platform, config.h defines

  #define _GL_EXTERN_INLINE_STDHEADER_BUG
  #define _GL_INLINE static _GL_UNUSED
  #define _GL_EXTERN_INLINE static _GL_UNUSED

That is, no inlining is performed, and the reference to pthread_create
ends up in the file test-thread_self.o.

This patch fixes it, by moving the reference to pthread_create away from
the header file.


2021-06-07  Bruno Haible  <bruno@clisp.org>

        thread: Fix test link error on DragonFly BSD 6.0.
        * lib/glthread/thread.c (gl_thread_create): Moved to here...
        * lib/glthread/thread.h (gl_thread_create): ...from here.
        (_GLTHREAD_THREAD_INLINE): Remove macro.
        Remove _GL_INLINE_HEADER_BEGIN/END invocations.

diff --git a/lib/glthread/thread.c b/lib/glthread/thread.c
index 38ba85d..de44932 100644
--- a/lib/glthread/thread.c
+++ b/lib/glthread/thread.c
@@ -20,7 +20,6 @@
 #include <config.h>
 
 /* Specification.  */
-# define _GLTHREAD_THREAD_INLINE _GL_EXTERN_INLINE
 #include "glthread/thread.h"
 
 #include <stdlib.h>
@@ -203,3 +202,15 @@ const gl_thread_t gl_null_thread /* = { .p = NULL } */;
 #endif
 
 /* ========================================================================= */
+
+gl_thread_t
+gl_thread_create (void *(*func) (void *arg), void *arg)
+{
+  gl_thread_t thread;
+  int ret;
+
+  ret = glthread_create (&thread, func, arg);
+  if (ret != 0)
+    abort ();
+  return thread;
+}
diff --git a/lib/glthread/thread.h b/lib/glthread/thread.h
index 1de9dcb..3e84599 100644
--- a/lib/glthread/thread.h
+++ b/lib/glthread/thread.h
@@ -83,14 +83,6 @@
 # endif
 #endif
 
-#ifndef _GL_INLINE_HEADER_BEGIN
- #error "Please include config.h first."
-#endif
-_GL_INLINE_HEADER_BEGIN
-#ifndef _GLTHREAD_THREAD_INLINE
-# define _GLTHREAD_THREAD_INLINE _GL_INLINE
-#endif
-
 /* ========================================================================= */
 
 #if USE_ISOC_THREADS
@@ -314,17 +306,7 @@ typedef int gl_thread_t;
 extern "C" {
 #endif
 
-_GLTHREAD_THREAD_INLINE gl_thread_t
-gl_thread_create (void *(*func) (void *arg), void *arg)
-{
-  gl_thread_t thread;
-  int ret;
-
-  ret = glthread_create (&thread, func, arg);
-  if (ret != 0)
-    abort ();
-  return thread;
-}
+extern gl_thread_t gl_thread_create (void *(*func) (void *arg), void *arg);
 #define gl_thread_sigmask(HOW, SET, OSET)     \
    do                                         \
      {                                        \
@@ -351,6 +333,4 @@ gl_thread_create (void *(*func) (void *arg), void *arg)
 }
 #endif
 
-_GL_INLINE_HEADER_END
-
 #endif /* _GLTHREAD_THREAD_H */