Re: Regression tests fail with musl libc because libpq.so can't be loaded

I wrote:
> Thomas Munro <thomas(dot)munro(at)gmail(dot)com> writes:
>> I had originally proposed to avoid anything beginning "LD_" but Tom
>> suggested being more specific. I doubt LD_PRELOAD can really hurt you
>> though (the linker probably only needs the value at the start by
>> definition, not at later dlopen() time (?)).

> Oh, good point. So we could simplify the patch by only looking for
> LD_LIBRARY_PATH.

I looked at the musl source code you identified and confirmed that
only the LD_LIBRARY_PATH string is remembered in a static variable;
LD_PRELOAD is only accessed locally in that initialization function.
So we only need to do the attached. (I failed to resist the
temptation to rewrite the comments.)

regards, tom lane