Postpone LLVM-related uses of AC_CHECK_DECLS.
Calling AC_CHECK_DECLS before we've finished setting up the compiler's
CFLAGS seems like a pretty risky proposition, especially now that the
first use of that macro will result in a test to see whether the compiler
gives warning or error for undeclared built-in functions. That answer
could very easily get changed later than where PGAC_LLVM_SUPPORT is
called; furthermore, it's hardly unlikely that flags such as -D_GNU_SOURCE
could change visibility of declarations. Hence, be a little less cavalier
about where to do LLVM-related tests. This results in v11 and HEAD doing
the warning-or-error check at the same place in the script as older
branches are doing it, which seems like a good thing.
Per further thought about commits 0b59b0e8b and 16fbac39f.
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/640a4ba052c2dd7aaf600ca13b6d3afca60adc05
Modified Files
--------------
config/llvm.m4 | 31 +++--
configure | 406 +++++++++++++++++++++++++++++----------------------------
configure.in | 4 +
3 files changed, 230 insertions(+), 211 deletions(-)