Fix configure's AC_CHECK_DECLS tests to work correctly with clang. The test case that Autoconf uses to discover whether a function has been declared doesn't work reliably with clang, because clang reports a warning not an error if the name is a known built-in function. On some platforms, this results in a lot of compile-time warnings about strlcpy and related functions not having been declared.
There is a fix for this (by Noah Misch) in the upstream Autoconf sources, but since they've not made a release in years and show no indication of doing so anytime soon, let's just absorb their fix directly. We can revert this when and if we update to a newer Autoconf release. Back-patch to all supported branches. Discussion: https://postgr.es/m/[email protected] Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/16fbac39ff68a737317f6fc7be78cc93a14856af Modified Files -------------- aclocal.m4 | 1 + config/check_decls.m4 | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++ configure | 104 ++++++++++++++++++++++++++++++++++++++++++-- configure.in | 9 ++-- 4 files changed, 223 insertions(+), 7 deletions(-)
