[glibmm] (6 commits) Non-fast-forward update to branch glibmm-2-56.nmake

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

The branch 'glibmm-2-56.nmake' 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:

  ebfe716... builds: Rename MSVC_Net2015 as MSVC_NMake
  685c8af... build: Split out automake-specific items from filelist.am's
  b4d3d2d... build: Add NMake Makefiles
  5642ba3... build: Remove Visual Studio 2015 projects
  f4a9af3... Update build instructions in README.win32

Commits added to the branch:

  6cd5549... tools/test_scripts/testheaders.sh: Fix a directory test (*)
  8215400... builds: Rename MSVC_Net2015 as MSVC_NMake
  669cbdd... build: Split out automake-specific items from filelist.am's
  d07bbfa... build: Add NMake Makefiles
  f017d0d... build: Remove Visual Studio 2015 projects
  3ff6b89... Update build instructions in README.win32

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