[gtkmm] (12 commits) Non-fast-forward update to branch use-dllexport

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

The branch 'use-dllexport' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  5544907... gdk/gdkmmconfig.h.[meson|in]: Add GDKMM_API
  e6acf4b... gtk/gtkmmconfig.h.[meson|in]: Re-organize GTKMM_API definit
  b56fdc9... gdk/src/*.hg: Mark classes and APIs with GDKMM_API
  b483ba4... gdk/gdkmm/*.h: Mark classes and APIs with GDKMM_API
  0fbae4f... class_gtkobject.m4: Add ability to decorate generated class
  7d13d76... gtk/src/*.hg: Mark classes and APIs with GTKMM_API
  9899d46... gtk/gtkmm/*.h: Mark classes and APIs with GTKMM_API
  ee4319d... Meson: Build gtkmm directly for all builds
  8a87cb4... NMake Makefiles: Stop using gendef.exe
  33ff7e6... Drop gendef from the sources

Commits added to the branch:

  cec60d6... NMake Makefiles: Fix building test programs (*)
  f1dca0d... NMake Makefiles: Fix header "installation" (*)
  1ef657a... gdk/gdkmmconfig.h.[meson|in]: Add GDKMM_API
  1ff126d... gtk/gtkmmconfig.h.[meson|in]: Re-organize GTKMM_API definit
  8036942... gdk/src/*.hg: Mark classes and APIs with GDKMM_API
  efd3e96... gdk/gdkmm/*.h: Mark classes and APIs with GDKMM_API
  8358d39... class_gtkobject.m4: Add ability to decorate generated class
  fbe9097... gtk/src/*.hg: Mark classes and APIs with GTKMM_API
  e137e87... gtk/gtkmm/*.h: Mark classes and APIs with GTKMM_API
  b7099b7... Meson: Build gtkmm directly for all builds
  0f31e0d... NMake Makefiles: Stop using gendef.exe
  d7ed398... Drop gendef from the sources

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