[glibmm] (13 commits) ...Merge branch 'glibmm-master-use-dllexport' into 'master'

[Chun-wei Fan <fanchunwei src gnome org>]

Summary of changes:

  4c2b07e... meson: Use /utf-8 for Visual Studio builds (*)
  7fb2c6d... glib/glibmm/*.h: Mark classes and methods with GLIBMM_API (*)
  f12e03b... tools/m4: Allow one to decorate the generated wrap() protot (*)
  08e7d74... tools: Allow generating Glib:Error class with decorations (*)
  b55811e... glib/src: Decorate classes and methods with GLIBMM_API (*)
  d84be37... build: Do not use gendef.exe for glibmm (*)
  3f66ba7... gio/src/*.hg: Mark classes and functions with GIOMM_API (*)
  c2c96a5... gio/giomm/*.h: Mark classes and functions with GIOMM_API (*)
  cc62858... Visual Studio builds: build giomm without gendef (*)
  0bcdad1... build: Drop gendef (*)
  1f006ee... glibmm: Update glibmmconfig.h.[in|meson] for MSVC (*)
  7886822... meson: Do not allow static MSVC-style builds (*)
  5fdbaf9... Merge branch 'glibmm-master-use-dllexport' into 'master'

(*) This commit already existed in another branch; no separate mail sent