NetBSD 10: gcc12-libs expected in but not depended on

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Some very recent changes make some packages pull in gcc12-libs on
NetBSD 10 but there is some kind of dependency problem. The symptoms
are:

https://releng.netbsd.org/pkgreports/shadow/HEAD/NetBSD-10.0-x86_64/20250403.0918/darktable-5.0.0nb3/configure.log

=> Build dependency gcc12>=12.1.0nb1: found gcc12-12.4.0nb1
...
===> Creating toolchain wrappers for darktable-5.0.0nb3
ERROR: gcc12-libs>=12.1.0 is not installed; can't buildlink files.
*** Error code 1

https://releng.netbsd.org/pkgreports/shadow/HEAD/NetBSD-10.0-x86_64/20250403.0918/filelight-23.08.4nb7/configure.log

=> Build dependency gcc12>=12.1.0nb1: found gcc12-12.4.0nb1
...
===> Creating toolchain wrappers for filelight-23.08.4nb7
ERROR: gcc12-libs>=12.1.0 is not installed; can't buildlink files.
*** Error code 1

I thought it was caused by the libheif changes (darktable pulls it in)
but filelight doesn't depend on it. So perhaps a different common
cause, or two changes?

Also affected:
https://releng.netbsd.org/pkgreports/shadow/HEAD/NetBSD-10.0-x86_64/20250403.0918/libksysguard-5.27.10nb7/configure.log

Any ideas?
 Thomas