pkgbase: remove incorrect clang shlib requires

The FreeBSD-clang package contains a 32-bit shared object at
/usr/lib/clang/19/lib/freebsd/libclang_rt.asan-i386.so

This is expected, since clang uses this object when compiling for i386
targets with asan enabled.

What is not expected is that the FreeBSD-clang package currently depends
on 32-bit libc packages due to pkg's shared library analysis, making it
impossible to install pkgbase on x86_64 without any lib32 packages.

This commit leverages a new pkg feature implemented in [1], but could
be landed before a pkg version including that feature is released
without any ill effects. Unknown keys in package manifests are ignored.

[1]: https://github.com/freebsd/pkg/pull/2594

Reviewed by:	ivy
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D54792

release/packages/ucl/clang.ucl

@@ -7,3 +7,8 @@ deps {
 		version = "${VERSION}"
 	}
 }
+
+shlibs_required_ignore: [
+	"libc.so.7:32",
+	"libgcc_s.so.1:32",
+]