README.win32.md: Restore Visual Studio 2008/2010 support

It turns out that it is possible to use the Windows 8.0 SDK in Visual
Studio 2008 and 2010 officially, but requires a special setup in the
build command prompt.

Tell people how that special setup can be achieved, and restore the
extra instructions on building with Visual Studio 2008, as it is now
possible again.

README.win32.md

@@ -164,9 +164,27 @@ normally.
 ### Support for pre-2012 Visual Studio
 
 This release of GLib requires at least the Windows 8.0 SDK in order to be built
-successfully using Visual Studio, which means that it is no longer supported to
-build GLib with Visual Studio 2008 nor 2010.  People that still need to use
-Visual Studio 2008 or 2010 should continue to use glib-2.66.x.
+successfully using Visual Studio, which means that building with Visual Studio
+2008 or 2010 is possible only with a special setup and must be done in the
+command line with Ninja.  Please see
+https://devblogs.microsoft.com/cppblog/using-the-windows-software-development-kit-sdk-for-windows-8-consumer-preview-with-visual-studio-2010/
+for references; basically, assuming that your Windows 8.0 SDK is installed in
+`C:\Program Files (x86)\Windows Kits\8.0` (`$(WIN8SDKDIR)` in short), you need
+to ensure the following before invoking Meson to configure the build:
+
+- Your `%INCLUDE%` must not include the Windows 7.0/7.1 SDK include directories,
+  and `$(WIN8SDKDIR)\include\um`, `$(WIN8SDKDIR)\include\um\share` and
+  `$(WIN8SDKDIR)\include\winrt` (in this order) must be before your stock
+  Visual Studio 2008/2010 header directories.  If you have the DirectX SDK installed,
+  you should remove its include directory from your `%INCLUDE%` as well.
+- You must replace the Windows 7.0/7.1 SDK library directory in `%LIB%` with the
+  Windows 8.0 SDK library directory, i.e. `$(WIN8SDKDIR)\lib\win8\um\[x86|x64]`.
+  If you have the DirectX SDK installed, you should remove its library directory
+  from your `%INCLUDE%` as well.
+- You must replace the Windows 7.0/7.1 SDK tools directory from your `%PATH%` with
+  the Windows 8.0 SDK tools directory, i.e. `$(WIN8SDKDIR)\bin\[x86|x64]`.
+  If you have the DirectX SDK installed, you should remove its utility directory
+  from your `%PATH%` as well.
 
 The Windows 8.0 SDK headers may contain an `roapi.h` that cannot be used under plain
 C, so to remedy that, change the following lines (around lines 55-57):
@@ -193,3 +211,23 @@ This follows what is done in the Windows 8.1 SDK, which contains an `roapi.h`
 that is usable under plain C.  Please note that you might need to copy that file
 into a location that is in your `%INCLUDE%` which precedes the include path for the
 Windows 8.0 SDK headers, if you do not have administrative privileges.
+
+### Visual Studio 2008 hacks
+
+- You need to run the following lines from your build directory, to embed the
+  manifests that are generated during the build, assuming the built binaries
+  are installed to `$(PREFIX)`, after a successful build/installation:
+
+```cmd
+> for /r %f in (*.dll.manifest) do if exist $(PREFIX)\bin\%~nf mt /manifest %f (PREFIX)\bin\%~nf;2
+> for /r %f in (*.exe.manifest) do if exist $(PREFIX)\bin\%~nf mt /manifest %f (PREFIX)\bin\%~nf;1
+```
+
+
+- If building for amd64/x86_64/x64, sometimes the compilation of sources may seem to hang, which
+  is caused by an optimization issue in the 2008 x64 compiler.  You need to use Task Manager to
+  remove all running instances of `cl.exe`, which will cause the build process to terminate.  Update
+  the build flags of the sources that hang on compilation by changing its `"/O2"` flag to `"/O1"`
+  in `build.ninja`, and retry the build, where things should continue to build normally.  At the
+  time of writing, this is needed for compiling `glib/gtestutils.c`, `gio/gsettings.c`,
+  `gio/gsettingsschema.c`, `glib/tests/fileutils.c` and `gio/tests/gsubprocess-testprog.c`