Report warning/error locations in a format IDEs may already know how to parse

Examples:

meson.build:2:0: ERROR: Dependency is both required and not-found
meson.build:4: WARNING: Keyword argument "link_with" defined multiple times.

These are already matched by the default compilation-error-regexp-alist in
emacs.

Also:
Don't start 'red' markup until after the \n before an error
Unabsorb full-stop at end of warning with location from mlog.warning()
Update warning_location test

1 files changed, 5 insertions, 2 deletions

diff --git a/mesonbuild/mlog.py b/mesonbuild/mlog.py
index aa2ac20..273552d 100644
--- a/mesonbuild/mlog.py
+++ b/mesonbuild/mlog.py
@@ -105,12 +105,15 @@ def log(*args, **kwargs):
 def warning(*args, **kwargs):
     from . import environment
 
+    args = (yellow('WARNING:'),) + args
+
     if kwargs.get('location'):
         location = kwargs['location']
         del kwargs['location']
-        args += ('in file {}, line {}.'.format(os.path.join(location.subdir, environment.build_filename), location.lineno),)
+        location = '{}:{}:'.format(os.path.join(location.subdir, environment.build_filename), location.lineno)
+        args = (location,) + args
 
-    log(yellow('WARNING:'), *args, **kwargs)
+    log(*args, **kwargs)
 
 # Format a list for logging purposes as a string. It separates
 # all but the last item with commas, and the last with 'and'.