Fix configure's AC_CHECK_DECLS tests to work correctly with clang.

Tom Lane <tgl@sss.pgh.pa.us>

Commit: f6ce9cee620702d8df551cd25761169f45503dc9
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: 2022-09-21T19:42:00Z
Fix configure's AC_CHECK_DECLS tests to work correctly with clang.

Back-port commit 16fbac39f into 9.3 and 9.2, so that these
out-of-support branches can be built with clang without wading
through a pile of warnings about strlcpy and related functions.
check_decls.m4 required some adaptation to work with autoconf 2.63,
but nothing too major.

Discussion: https://postgr.es/m/26819.1542515567@sss.pgh.pa.us
Discussion: https://postgr.es/m/1081321.1663775084@sss.pgh.pa.us

Files

PathChange+/−
aclocal.m4 modified +1 −0
config/check_decls.m4 added +112 −0
configure modified +192 −10
configure.in modified +3 −2

Discussion