Log Message:
Add a workaround for PR 45266 (krb5-config issue in NetBSD base):
clear BUILDLINK_INCDIRS.heimdal. Otherwise -I/usr/include/krb5 appears
in CFLAGS, which breaks the build because the compiler finds krb5's
base64.h instead of Amaya's. krb5 is pulled in by curl, which is a
several-times-indirect dependency, and nothing in this package uses
it, or apparently anything that needs it, directly.