[gcc/devel/omp/gcc-12] Make 'libgcc/config/nvptx/crt0.c' build '--without-headers'

[Thomas Schwinge <tschwinge@gcc.gnu.org>]

https://gcc.gnu.org/g:d90a8a5685c8bd3657892feac01739fe87a457a5

commit d90a8a5685c8bd3657892feac01739fe87a457a5
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Tue Jan 24 09:49:34 2023 +0100

    Make 'libgcc/config/nvptx/crt0.c' build '--without-headers'
    
    ..., where it currently fails:
    
        [...]/libgcc/config/nvptx/crt0.c:22:10: fatal error: stdlib.h: No such file or directory
           22 | #include <stdlib.h>
              |          ^~~~~~~~~~
    
    Fix-up for "nvptx: Support global constructors/destructors via 'collect2'".
    
            libgcc/
            * config/nvptx/crt0.c [!HAVE_STDLIB_H]: Don't '#include <stdlib.h>'.
            (atexit): Prototype.

Diff:
---
 libgcc/ChangeLog.omp       | 5 +++++
 libgcc/config/nvptx/crt0.c | 7 ++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/libgcc/ChangeLog.omp b/libgcc/ChangeLog.omp
index c46f49bf5b7..cf509a70d61 100644
--- a/libgcc/ChangeLog.omp
+++ b/libgcc/ChangeLog.omp
@@ -1,3 +1,8 @@
+2023-01-24  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* config/nvptx/crt0.c [!HAVE_STDLIB_H]: Don't '#include <stdlib.h>'.
+	(atexit): Prototype.
+
 2023-01-20  Thomas Schwinge  <thomas@codesourcery.com>
 	    Andrew Stubbs  <ams@codesourcery.com>
 
diff --git a/libgcc/config/nvptx/crt0.c b/libgcc/config/nvptx/crt0.c
index 860e2bfacad..02648bef84b 100644
--- a/libgcc/config/nvptx/crt0.c
+++ b/libgcc/config/nvptx/crt0.c
@@ -19,11 +19,16 @@
    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <stdlib.h>
+#include "auto-target.h"
+
+#ifdef HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
 #include "gbl-ctors.h"
 
 int *__exitval_ptr;
 
+extern int atexit (void (*function) (void));
 extern void __attribute__((noreturn)) exit (int status);
 extern int main (int, void **);