With this optimization flag enabled, recent versions of gcc can generate
incorrect code that assumes variable-length arrays (such as oidvector)
are actually fixed-length because they're embedded in some larger struct.
The known instance of this problem was fixed in 9.2 and up by commit
8137f2c32322c624e0431fac1621e8e9315202f9 and followon work, which hides
actually-variable-length catalog fields from the compiler altogether.
And we plan to gradually convert variable-length fields to official
"flexible array member" notation over time, which should prevent this type
of bug from reappearing as gcc gets smarter. We're not going to try to
back-port those changes into older branches, though, so apply this
band-aid instead.
Andres Freund
This is a backpatch of commit 649839dd9 to unsupported branches
REL8_2_STABLE and REL8_3_STABLE, so that they work with newer toolsets.
Suggested solution from Tom Lane. Problem discovered, probably not
for the first time, while testing the mingw-w64 32 bit compiler.
Backpatched to all live branches.
The version of this macro used in autoconf 2.59 is capable of incorrectly
succeeding (ie, reporting that a library function is available when it
isn't), if the compiler performs link-time optimization and decides that
it can optimize the function reference away entirely. Replace it with the
coding used in autoconf 2.61 and later, which forces the program result to
depend on the function's result so that it cannot be optimized away. This
should fix build failures currently being seen on buildfarm member anchovy.
This patch affects the 8.2 and 8.3 branches only, since later branches are
using autoconf versions that don't have this problem.
We previously found out that OS X's standard perl installation tries to put
-arch switches into Perl link commands, evidently in hopes of building
universal binaries. But it doesn't work to add such switches in plperl's
link step if they weren't being used earlier, so this is basically
unworkable. When using gcc the result is only some warnings; but LLVM
fails entirely, so this issue isn't as cosmetic as we originally thought.
Hence, back-patch commit d69a419e682c2d39c2355105a7e5e2b90357c8f0 into
pre-9.0 branches.
The mingw people don't appear to care about compatibility with non-GNU
versions of getopt, so force use of our own copy of getopt on Windows.
Also, ensure that we make use of optreset when using our own copy.
Per report from Andrew Dunstan. Back-patch to all versions supported
on Windows.
This prevents compiler optimizations that assume overflow won't occur, which
breaks numerous overflow tests that we need to have working. It is known
that gcc 4.3 causes problems and possible that 4.1 does. Per my proposal
of some time ago and a recent report from Kris Jurka.
Backpatch as far as 8.0, which is as far as the patch conveniently goes.
7.x was pretty short of overflow tests anyway, so it may not matter there,
even assuming that anyone cares whether 7.x builds on recent gcc.
unportable backslashes in awk script (per Patrick Welche), and add
brackets to prevent autoconf from mangling sed's regexp (the sed call
here never did what was expected).
include it if it links properly. It seems too risky to assume that
standard functions like pow() are not special-cased by the compiler.
Per report from Andreas Lange that build fails on Solaris cc compiler
with -fast. Even though we don't consider that a supported option,
I'm worried that similar issues will arise with other compilers.
code relies on the checking macro actually being called at the end, or the
automatic undiversion will produce garbage. These sort of implicit
side-effects undermine the modularity of the macros and happen to break the
ODBC driver which makes use of them.
Also put the warnings at the very end of configure, so there is an even
better chance of seeing them.
