Am 17.10.2018 um 16:28 schrieb Tom Lane <tgl@sss.pgh.pa.us>:
> It's also very odd,
> if the compiler will search the sysroot automatically, why that seemingly
> works for tcl.h but not perl.h. plperl definitely still fails if you
> lobotomize the PG_SYSROOT logic.
Because pl/tcl ends up using -iwithsysroot to specify the header search path and pl/perl uses -I
See also: https://www.postgresql.org/message-id/153558865647.1483.573481613491501077%40wrigleys.postgresql.org
I would assume that clang sets -isysroot automatically, but I have no idea why that didn't work for you previously.
Jakob
