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
@@ -140,7 +140,7 @@ do_system (const char *line)
   __posix_spawnattr_setflags (&spawn_attr,
 			      POSIX_SPAWN_SETSIGDEF | POSIX_SPAWN_SETSIGMASK);
 
-  status = __posix_spawn (&pid, SHELL_PATH, 0, &spawn_attr,
+  status = posix_spawnp (&pid, SHELL_NAME, 0, &spawn_attr,
 			  (char *const[]){ (char*) SHELL_NAME,
 					   (char*) "-c",
 					   (char *) line, NULL },
--- a/libio/iopopen.c
+++ b/libio/iopopen.c
@@ -85,7 +85,7 @@ spawn_process (posix_spawn_file_actions_t *fa, FILE *fp, const char *command,
 	return false;
     }
 
-  if (__posix_spawn (&((_IO_proc_file *) fp)->pid, _PATH_BSHELL, fa, 0,
+  if (posix_spawnp (&((_IO_proc_file *) fp)->pid, "sh", fa, 0,
 		     (char *const[]){ (char*) "sh", (char*) "-c",
 		     (char *) command, NULL }, __environ) != 0)
     return false;