[Bug libfortran/90038] execute_command_line should not use fork()

[jb at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90038

--- Comment #7 from Janne Blomqvist <jb at gcc dot gnu.org> ---
This should fix it:

--- a/libgfortran/intrinsics/execute_command_line.c
+++ b/libgfortran/intrinsics/execute_command_line.c
@@ -34,6 +34,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If
not, see
 #endif
 #ifdef HAVE_POSIX_SPAWN
 #include <spawn.h>
+#include <signal.h>
 extern char **environ;
 #endif

@@ -83,6 +84,9 @@ execute_command_line (const char *command, bool wait, int
*exitstat,
       set_cmdstat (cmdstat, EXEC_NOERROR);

 #ifdef HAVE_POSIX_SPAWN
+      /* As of POSIX.1-2001, setting SIGCHLD to SIG_IGN makes the
+        kernel automatically reap zombies.  */
+      signal (SIGCHLD, SIG_IGN);
       const char * const argv[] = {"sh", "-c", cmd, NULL};
       if (posix_spawn (&pid, "/bin/sh", NULL, NULL,
                       (char * const* restrict) argv, environ))