[PATCH] build: fix libpcap detection with unusable header

[Bruce Richardson]

On Wed, Jul 08, 2026 at 06:37:59AM +0000, Maayan Kashani wrote:
> Hi, Bruce, we encountered DPDK build issue on Tencent 4.6.  It is not
> expected; the package/image appears corrupted.  RPM verification confirms
> the headers differ from the packaged contents.  The DPDK change is still
> valid because optional dependency detection should test for usable
> declarations, not just file existence and library presence.”
> 
I would disagree. Following that logic of checking for broken packages,
you're only handling a very small subset of that. If we start checking
this, we really should check for each and every definition in the file that
we need - otherwise we can still have issues with a broken package, for
example, it's broken in missing one definition that we need.

IMHO, in all these cases its better to let things fail, rather than working
around them, in order to prompt correction of the broken package.

/Bruce