There seems to be an issue with compilation-mode highlighting in
recent Emacs master. Not all lines that match the regexp alist
are highlighted. See attached screenshot for an example.
The "checking" lines are highlighted more or less at random.
There are errors from jit-lock (see below).

In GNU Emacs 26.0.50 (build 2, x86_64-w64-mingw32)
 of 2017-09-02 built on MACHINE
Repository revision: f2a074830c588d2a1c240afbd709a029a4c1a42f
Windowing system distributor 'Microsoft Corp.', version 10.0.15063
Recent messages:
Error during redisplay: (jit-lock-function 2553) signaled
(void-function compilation-face)
Error during redisplay: (jit-lock-function 2616) signaled
(void-function compilation-face)
Error during redisplay: (jit-lock-function 2645) signaled
(void-function compilation-face)
Error during redisplay: (jit-lock-function 2674) signaled
(void-function compilation-face)
Error during redisplay: (jit-lock-function 2733) signaled
(void-function compilation-face) [2 times]
Error during redisplay: (jit-lock-function 2764) signaled
(void-function compilation-face)
Error during redisplay: (jit-lock-function 2793) signaled
(void-function compilation-face)
Error during redisplay: (jit-lock-function 2822) signaled
(void-function compilation-face)
Error during redisplay: (jit-lock-function 2862) signaled
(void-function compilation-face)
Error during redisplay: (jit-lock-function 2995) signaled
(void-function compilation-face)

Configured using:
 'configure --config-cache --with-modules --without-pop CFLAGS=-Ofast'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS MODULES

Important settings:
  value of $EMACSLOADPATH: c:\emacs-lisp;
  value of $LANG: ENG
  locale-coding-system: cp1252

Major mode: Compilation

Minor modes in effect:
  shell-dirtrack-mode: t
  diff-auto-refine-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr misearch multi-isearch emacsbug message subr-x
puny dired dired-loaddefs format-spec rfc822 mml mml-sec password-cache
epa derived epg epg-config gnus-util rmail rmail-loaddefs mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils shell
pcomplete compile comint ansi-color ring vc-git diff-mode easy-mmode map
seq byte-opt gv bytecomp byte-compile cconv cl-loaddefs cl-lib bat-mode
easymenu elec-pair time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel dos-w32 ls-lisp disp-table
term/w32-win w32-win w32-vars term/common-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote w32notify w32 multi-tty make-network-process emacs)

Memory information:
((conses 16 110759 24525)
 (symbols 56 21338 1)
 (miscs 48 69 194)
 (strings 32 33412 1339)
 (string-bytes 1 872517)
 (vectors 16 16549)
 (vector-slots 8 506344 10373)
 (floats 8 61 181)
 (intervals 56 849 128)
 (buffers 992 14))