Show number of errors in compilation-mode mode-line

Bug#25354
* lisp/progmodes/compile.el (compilation-num-errors-found): Provide
default value.
(compilation-num-warnings-found, compilation-num-infos-found): New
defvars.
(compilation-mode-line-errors): New defconst.
(compilation-face): Remove.
(compilation-type, compilation--note-type): New functions.
(compilation-parse-errors): Call compilation--note-type.
(compilation-start): Include compilation-mode-line-errors in
mode-line-process.
(compilation-setup): Initialize compilation-num-* variables to 0.
(compilation-handle-exit): Include compilation-mode-line-errors in
mode-line-process.
* doc/emacs/building.texi (Compilation): Document new feature.

1 files changed, 4 insertions, 0 deletions

diff --git a/doc/emacs/building.texi b/doc/emacs/building.texi
index f7eb8fe9eaf..cc79eae7770 100644
--- a/doc/emacs/building.texi
+++ b/doc/emacs/building.texi
@@ -90,6 +90,10 @@ inserted above point, which remains at the end.  Otherwise, point
 remains fixed while compilation output is added at the end of the
 buffer.
 
+  While compilation proceeds, the mode line is updated to show the
+number of errors, warnings, and informational messages that have been
+seen so far.
+
 @cindex compilation buffer, keeping point at end
 @vindex compilation-scroll-output
   If you change the variable @code{compilation-scroll-output} to a