Hello Dub,
The short reason why gtk-update-icon-cache.exe is because AFAICT there
isn't much of a need for it, at least for MSVC builds of GTK+.
The longer explanation
for this is this:
The reason why the icons are broken is that you will need some
additional packages, namely:
-hicolor-icon-theme
-adwaita-icon-theme
Suppose you have your GTK+ DLLs in c:\foo\bin...
To make things relocatable on Windows without much text file editing, we
need to use the fallback icon theme mechanism here-You need to put the
index.theme file from hicolor-icon-theme into c:\foo\share\icons\hicolor
(create the folder if needed), then you need to extract everything
within the Adwaita folder in
adwaita-icon-theme to
c:\foo\share\icons\hicolor. Doing these will get make some icons show
(see note below), and the warnings of icon not being found go away.
Note: in the current release state (GTK+ 3.13.5 and adwaita-icon-theme
3.13.4), librsvg (which depends on libcroco and libxml2) is needed to
display many of the icons, known as symbolic icons. A utility program
has been added to GTK+ master recently (so it will be in its next
unstable release) to convert those images into .png format so that these
icons will show even on systems without librsvg installed (but: running
that utility itself
requires the rsvg gdk-pixbuf loader, which, itself
is from librsvg). There isn't ready-made Visual C++ support for
building librsvg in GIT at this time, so let me know if adding such
support to librsvg would be desirable, or let me (us, since those png
symbolic icons will be generated on the fly from adwaita-icon-theme)
know if having the symbolic icons in png format distributed would be
needed. I will put on the MSVC building guide page the icons that have
been converted, but it might be so that they go out of date (or, is it
desirable that I have some where on the public GNOME servers where I can
put them?)
Sorry for the lengthy response, but hope this helps.
With blessings.