Merge from origin/emacs-26

Merge from origin/emacs-26

54fb383 (origin/emacs-26) Fix detection of freed emacs_values (Bug#32...
769d0cd ; Fix out-of-tree build for mod-test.so
9a1329e Avoid crashes with very wide TTY frames on MS-Windows
9a613d3 Prevent `modify-file-local-variable-prop-line' from adding ex...
624e7dc Update GNOME bugtracker URLs
51ef6d5 Clarify in the Emacs manual that ChangeLog files are not used
6e08019 Recognize codepage 65001 as a valid encoding
1a350d7 ; * etc/NEWS: Fix format of first lines of some entries.
22d1f53 Avoid compilation warning in nt/addpm.c
7bc9ce7 Fix duplicate custom group names in bibtex.el
a9cf938 Fix outdated text in the Calc manual

Conflicts:
	etc/NEWS
	etc/PROBLEMS
	src/emacs-module.c
	src/gtkutil.c
	src/image.c
	src/xterm.c
	test/Makefile.in