Merge from origin/emacs-25

6e3adf8 Fix crash in syntax.c after GC
973ce5a Improve squiggly heredoc support in non-SMIE Ruby mode
9d5cceb Fix doc string quoting
0b33a23 Fix mouse dragging of vertical dividers with scroll bars on l...
a5d05f4 * etc/PROBLEMS: Mention the link-time problems on FreeBSD 11.

diff --cc etc/PROBLEMS
Simple merge

diff --cc lisp/files.el
Simple merge

diff --cc lisp/mouse.el
Simple merge

diff --cc lisp/subr.el
Simple merge

diff --cc src/syntax.c
Simple merge