Merge from origin/emacs-26

134edc1 Warn about wrong number of args for subrs (Bug#35767)
5f01af6 Use plain symbols for eieio type descriptors (Bug#29220)
4b24b01 Pacify GCC 9 -Wredundant-decls

diff --cc lisp/emacs-lisp/bytecomp.el
Simple merge

diff --cc lisp/emacs-lisp/eieio-core.el
Simple merge

diff --cc lisp/emacs-lisp/eieio.el
Simple merge

diff --cc src/gmalloc.c
Simple merge

diff --cc test/lisp/emacs-lisp/bytecomp-tests.el
Simple merge

diff --cc test/lisp/emacs-lisp/eieio-tests/eieio-test-persist.el
Simple merge