We want to allow builds in chroots that lack /bin/sh.  Thus, system(3)
and popen(3) need to be tweaked to use the right shell.  For the bootstrap
glibc, we just use whatever `sh' can be found in $PATH.  The final glibc
instead uses the hard-coded absolute file name of `bash'.

--- a/sysdeps/posix/system.c
+++ b/sysdeps/posix/system.c
@@ -106,8 +106,8 @@ do_system (const char *line)
       (void) UNBLOCK;
 
       /* Exec the shell.  */
-      (void) __execve (SHELL_PATH, (char *const *) new_argv, __environ);
+      (void) execvp (SHELL_NAME, (char *const *) new_argv);
       _exit (127);
     }
   else if (pid < (pid_t) 0)
     /* The fork failed.  */
--- a/libio/iopopen.c
+++ b/libio/iopopen.c
@@ -170,7 +170,7 @@ _IO_new_proc_open (fp, command, mode)
       for (p = proc_file_chain; p; p = p->next)
 	_IO_close (_IO_fileno ((_IO_FILE *) p));
 
-      _IO_execl ("/bin/sh", "sh", "-c", command, (char *) 0);
+      execlp ("sh", "sh", "-c", command, (char *) 0);
       _IO__exit (127);
     }
   _IO_close (child_end);