bash: import upstream patches for 5.1

Source:
https://ftp.gnu.org/gnu/bash/bash-5.1-patches/bash51-001
https://ftp.gnu.org/gnu/bash/bash-5.1-patches/bash51-002
https://ftp.gnu.org/gnu/bash/bash-5.1-patches/bash51-003
https://ftp.gnu.org/gnu/bash/bash-5.1-patches/bash51-004

Signed-off-by: Huangbin Zhan <zhanhb88@gmail.com>

utils/bash/patches/102-bash51-002.patch

@@ -0,0 +1,45 @@
+			     BASH PATCH REPORT
+			     =================
+
+Bash-Release:	5.1
+Patch-ID:	bash51-002
+
+Bug-Reported-by:	oguzismailuysal@gmail.com
+Bug-Reference-ID:	<CAH7i3LoHFUa4aSF5-AD2r80HG-p-YzD_9ZxomarZkhP8NMq63g@mail.gmail.com>
+Bug-Reference-URL:	https://lists.gnu.org/archive/html/bug-bash/2020-12/msg00037.html
+
+Bug-Description:
+
+If there are no jobs, and the `-n' and `-p' options are both supplied to
+`wait', bash can assign a value to the variable name specified with `-p'
+instead of leaving it unset.
+
+Patch (apply with `patch -p0'):
+
+--- a/builtins/wait.def
++++ b/builtins/wait.def
+@@ -213,11 +213,11 @@ wait_builtin (list)
+ 	}
+ 
+       status = wait_for_any_job (wflags, &pstat);
+-      if (status < 0)
+-	status = 127;
+-
+       if (vname && status >= 0)
+ 	bind_var_to_int (vname, pstat.pid);
++
++      if (status < 0)
++	status = 127;
+       if (list)
+ 	unset_waitlist ();
+       WAIT_RETURN (status);
+--- a/patchlevel.h
++++ b/patchlevel.h
+@@ -25,6 +25,6 @@
+    regexp `^#define[ 	]*PATCHLEVEL', since that's what support/mkversion.sh
+    looks for to find the patch level (for the sccs version string). */
+ 
+-#define PATCHLEVEL 1
++#define PATCHLEVEL 2
+ 
+ #endif /* _PATCHLEVEL_H_ */