kconfig/devicetree: Print path to headers when configuring

[ulfalizer]

Change the output during CMake configure from

Devicetree configuration written to .../devicetree.conf
Parsing /home/ulf/z/z/Kconfig
Loaded configuration '.../frdm_kw41z_defconfig'
Merged configuration '.../prj.conf'
Configuration saved to '.../.config'

to

Devicetree header saved to '.../devicetree_unfixed.h'
Parsing /home/ulf/z/z/Kconfig
Loaded configuration '.../frdm_kw41z_defconfig'
Merged configuration '.../prj.conf'
Configuration saved to '.../.config'
Kconfig header saved to '.../autoconf.h'

devicetree_unfixed.h is more useful to be aware of than devicetree.conf
(still hoping we can get rid of it at some point), and seeing the
Kconfig header clarifies things to.

"Saved" instead of "written" for consistency. Maybe it could say
"Kconfig configuration" instead of "configuration" too, though it gets a
bit spammy in other contexts where the message shows up.

Updates Kconfiglib (and menuconfig/guiconfig, just to sync) to upstream
revision 061e71f7d7, to get this commit in, which is used to print the
header path:

Return a message from Kconfig.write_autoconf()

Like for Kconfig.write_config() and Kconfig.write_min_config(),
return a string from Kconfig.write_autoconf() with a message saying
that the header got saved, or that there were no changes to it. Can
be handy in tools.

Also make the "no change" message for the various files more
specific, by mentioning what type of file it is (configuration,
header, etc.)

Return True/False from Kconfig._write_if_changed() to indicate if
the file was updated. This also allows it to be reused in
Kconfig.write_min_config().

[ulfalizer]

Semi-unrelated, but #21560 might help with getting rid of devicetree.conf btw.

[SebastianBoe]

On my machine it doesn't say "Parsing <kconfig_source_file>", it says "Parsing Kconfig tree in <kconfig_source_file>".

[SebastianBoe]

We want to keep logs as short as possible, let us omit

Kconfig header saved to '.../autoconf.h'

autoconf.h is automatically included, so there is no need to know where it is.
.config is useful to know where is because it contains the resulting/active Kconfig'uration.

[ulfalizer]

On my machine it doesn't say "Parsing <kconfig_source_file>", it says "Parsing Kconfig tree in <kconfig_source_file>".

Changed in commit 45050dd ("kconfig/cmake: Improve reconfiguration behavior").

We want to keep logs as short as possible, let us omit

Kconfig header saved to '.../autoconf.h'

autoconf.h is automatically included, so there is no need to know where it is.
.config is useful to know where is because it contains the resulting/active Kconfig'uration.

Want to include it so that people coming at it fresh realize that there's a header. Helps with understanding how Kconfig works. Might think it's just the configuration file otherwise.

autoconf.h is a pretty bad name too. It's just consistent with the C tools.