bug#20869: Recent map-elt change broke 'make bootstrap'

[Paul Eggert]

This seems to be due to commit 8b6d82d3ca86f76ed964063b3941a7c6ab0bf1c6 so I am 
CC'ing Nicolas.  The symptoms:

  ELC      emacs-lisp/map.elc

In toplevel form:
emacs-lisp/map.el:125:5:Warning: gv-get called with 1 argument, but requires 2
emacs-lisp/map.el:128:1:Error: (map--raw-place map #[257 "\301\300E\207" [map 
setq] 4 "

(fn V)"]) is not a valid place expression
Makefile:268: recipe for target 'emacs-lisp/map.elc' failed
make[2]: *** [emacs-lisp/map.elc] Error 1
make[2]: Leaving directory '/home/eggert/src/gnu/emacs/static-checking/lisp'
Makefile:291: recipe for target 'compile-main' failed
make[1]: *** [compile-main] Error 2
make[1]: Leaving directory '/home/eggert/src/gnu/emacs/static-checking/lisp'
Makefile:385: recipe for target 'lisp' failed
make: *** [lisp] Error 2