.*-sun-solaris2.* 2 2.0.0 # just an arbitrary value
+.*-.*-freebsd.*-gnu.* 3 4.0.0 # earliest compatible kernel version
+
+.*-.*-knetbsd.*-gnu.* 4 1.6.0 # earliest compatible kernel version
+
+.*-.*-syllable.* 5 2.0.0 # just an arbitrary value
+
# There is no catch-all default here because every supported OS that uses
# ELF must have its own unique ABI tag.