[gimp] meson: add a libmypaint < 1.4.0 warning.

[Jehan <jehanp src gnome org>]

commit f9752f39b0f8ae3384a02ff25d9712ddeb9d0e91
Author: Jehan <jehan girinstud io>
Date:   Tue Nov 12 17:21:25 2019 +0100

    meson: add a libmypaint < 1.4.0 warning.
    
    Same as what I did for the configure script. Note that I break commits
    in 2 to make the autotools commits easily backportable to gimp-2-10,
    i.e. without any meson files.

 meson.build | 10 ++++++++++
 1 file changed, 10 insertions(+)
---
diff --git a/meson.build b/meson.build
index be3089f9ac..6e63b86bf4 100644
--- a/meson.build
+++ b/meson.build
@@ -352,6 +352,16 @@ lcms              = dependency('lcms2',              version: '>=2.8')
 
 libmypaint        = dependency('libmypaint',         version: '>=1.3.0')
 
+if not libmypaint.version().version_compare('>=1.4.0')
+  libmypaint_warning='''
+
+        libmypaint lower than version 1.4.0 is known to crash when
+        parsing MyPaint 2 brushes. Please update.
+    '''
+    warning(libmypaint_warning)
+    warnings += libmypaint_warning
+endif
+
 mypaint_brushes   = dependency('mypaint-brushes-1.0', version: '>=1.3.0')
 
 if relocatable_bundle