Re: FullTransactionId changes are causing portability issues

I wrote:
> Our Solaris packager reports that 12beta1 is failing to build for him
> on some Solaris variants:

>> The link failure is:
>> ---
>> Undefined first referenced
>> symbol in file
>> ReadNextFullTransactionId pg_checksums.o
>> ld: fatal: symbol referencing errors. No output written to pg_checksums
>> ---

On looking closer, the fix is simple and matches what we've done
elsewhere: transam.h needs to have "#ifndef FRONTEND" to protect
its static inline function from being compiled into frontend code.

So the disturbing thing here is that we no longer have any active
buildfarm members that can build HEAD but have the won't-elide-
unused-static-functions problem. Clearly we'd better close that
gap somehow ... anyone have an idea about how to test it better?

regards, tom lane