is_elf_format usage in ld testsuite?

[Andreas Tobler]

Hi all,

while getting an overview of the ld testsuite on powerpc64 FreeBSD I 
found the following.

ld-elf/binutils.exp:
---
# Make sure that binutils can correctly handle ld output in ELF.

if { ![istarget *-*-linux*]
      && ![istarget *-*-gnu*]} {
	return
}
---

These tests run fine under FreeBSD for example. But these targets are 
not on the test above.
Is there a special reason why we do not check with the is_elf_format 
proc instead?

There are a few more testcases with this pattern.
I can either add FreeBSD to the existing check or replace the test with 
the is_elf_format proc.

What do you think?

Thank you for any insight.
Andreas