"errno" not set in case of "libm" functions (HPUX)

I have found a problem which is specifically related to "HP-UX" compiler.
All 'libm' functions on "HP-UX Integrity server" do not set "errno" by
default. For 'errno' setting we should compile the code using +Olibmerrno
option. So we should add this option in "/src/makefiles/Makefile.hpux".
Otherwise we cannot expect this code to work properly

[float.c]
Datum
dacos(PG_FUNCTION_ARGS)
{
...
errno = 0;
result = acos(arg1);
if (errno != 0)
ereport(ERROR,

(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("input is out of range")));

...
}

Because "acos" function will not set the errono in case of invalid input, so
check will not trigger the error message. I have attached a patch to add
this option in HPUX makefile.

BTW I have found same kind of discussion without any conclusion here

http://archives.postgresql.org/pgsql-hackers/2011-05/msg00046.php

--
Ibrar Ahmed