external/firebird: Work around operator new alignment violations

...causing problems at least when building with recent Clang trunk on
x86_64-unknown-linux-gnu:

> make[5]: Entering directory 'workdir/UnpackedTarball/firebird/gen'
> rm -f metadata.fdb
> core/workdir/UnpackedTarball/firebird/gen/Release/firebird/bin/isql -q -i workdir/UnpackedTarball/firebird/src/dbs/metadata.sql
> Makefile:325: recipe for target 'metadata.fdb' failed
> make[5]: *** [metadata.fdb] Segmentation fault (core dumped)

See the mail thread starting at
<https://sourceforge.net/p/firebird/mailman/firebird-devel/thread/ec7c3bb1-3fef-e9b8-5b23-0d07fc412f95%40redhat.com/#msg35669676>
"[Firebird-devel] alloc.h global operator new replacement violating alignment
requirements".  With DEBUG_GDS_ALLOC defined, the allocation functions defined
in src/common/classes/alloc.h are no longer replacements of standard allocation
functions, so Clang happens to not make aggressive alignment assumptions, see
the mail thread starting at
<http://lists.llvm.org/pipermail/cfe-dev/2017-February/052676.html> "[cfe-dev]
operator new alignment assumptions".

(Instead of always defining DEBUG_GDS_ALLOC, I first tried to comment out the
definitions of global operator new/delete replacement functions in alloc.h,
falling back to the compiler-provided versions.  But many places in Firebird
allocate via Firebird-specific operator new placement overrides and deallocate
via delete expressions, which happens to work at runtime when the replaceable
operator delete is Firebird's, but not when it is the compiler-provided one.)

Change-Id: Ie02adb440fa959b723983d7f5b0246d3634dc06b

0 files changed, 0 insertions, 0 deletions