Improve ECMAddAppIconMacro.

Summary:
- Add support for SIDEBAR_ICONS on macOS
- Allow specifying a basename for the icon file via OUTFILE_BASENAME
- Add support for HiRes icons on Windows via icotool

I'm sorry this went all into one big change. I see that it's not optimal,
but it's really hard to rip it apart...

Also to me the whole code with support for two flavors of png2ico and icotool seems very spaghetti-ish. IMHO there's no good reason to keep supporting all three, icotool is the only maintained project and the only one supporting more than 128px wide icons. That's why I would suggest to simplify the whole code by only supporting icotool in one of the next releases.

Test Plan:
We use this version of ECMAddAppIconMacro in ownCloud client and it works...
I tested icotool natively and while cross-compiling on linux.

SIDEBAR_ICONS are also working...

If you want to test this with the ownCloud client, it's best to use
https://github.com/dschmidt/owncloud-client/tree/fix-app-icon-macro
because that contains a small fix I just PR'ed and which is not
in master yet. (We maintain a fork of the module there, so compiling it for Windows or macOS will automatically use the version of the module that I'm submitting)

Reviewers: vonreth, vpinon, apol, alexmerry, cgiboudeaux

Reviewed By: cgiboudeaux

Subscribers: cgiboudeaux, kde-frameworks-devel, kde-buildsystem

Tags: #frameworks, #build_system

Differential Revision: https://phabricator.kde.org/D13698

1 files changed, 1 insertions, 0 deletions

diff --git a/docs/find-module/FindIcoTool.rst b/docs/find-module/FindIcoTool.rst
new file mode 100644
index 00000000..ec088a6b
--- /dev/null
+++ b/docs/find-module/FindIcoTool.rst
@@ -0,0 +1 @@
+.. ecm-module:: ../../find-modules/FindIcoTool.cmake