The canonical config file is in src/backend/gpopt/.clang-format (instead
of under the non-existent src/backend/gporca), I've created one (instead
of two) symlink, for GPOPT headers. Care has been taken to repoint the
symlink to the canonical config under gpopt, instead of gpopt as it is
under HEAD.

This is spiritually a cherry-pick of commit 2f7dd76c.
(cherry picked from commit 2f7dd76c)

- Fix "missing prototype" warnings
- Fix "generalized initializer lists are a C++ extension" warning

funcs.cpp:43:1: warning: no previous prototype for function 'DisableXform' [-Wmissing-prototypes]
DisableXform(PG_FUNCTION_ARGS)
^
funcs.cpp:76:1: warning: no previous prototype for function 'EnableXform' [-Wmissing-prototypes]
EnableXform(PG_FUNCTION_ARGS)
^
funcs.cpp:109:1: warning: no previous prototype for function 'LibraryVersion' [-Wmissing-prototypes]
LibraryVersion()
^
funcs.cpp:123:1: warning: no previous prototype for function 'OptVersion' [-Wmissing-prototypes]
OptVersion()
^
4 warnings generated.

CTranslatorDXLToScalar.cpp:730:9: warning: generalized initializer lists are a C++11 extension [-Wc++11-extensions]
        return { .oid_type = inner_type_oid, .type_modifier = type_modifier};

As part of moving away from Hungarian notation in the GPORCA codebase,
the integration points between GPORCA and GPDB in the translator have
been renamed to the new convention used in GPORCA. The libraries
currently updated to the new notation in GPORCA are Naucrates and GPOS.
The new naming convention is a custom version of common C++ naming
conventions. The style guide for this convention can be found in the
GPORCA repository.

Also bump ORCA version to 2.69.0
Co-authored-by: NShreedhar Hardikar <shardikar@pivotal.io>
Co-authored-by: NMelanie Plageman <mplageman@pivotal.io>
Co-authored-by: NEkta Khanna <ekhanna@pivotal.io>
Co-authored-by: NAbhijit Subramanya <asubramanya@pivotal.io>
Co-authored-by: NSambitesh Dash <sdash@pivotal.io&gt;&lt;Paste>
Co-authored-by: NDhanashree Kashid <dkashid@pivotal.io>
Co-authored-by: NOmer Arap <oarap@pivotal.io>

Using a StringInfo just to copy a string is quite pointless. Simplify by
changing OptVersion() to return a plain palloc'd string instead.

This fixes a memory management bug too: OptVersion() is called like a
normal Postgres C function, not as a subroutine of PplStmtOptimize. As a
result, if OptVersion() throws a C++ exception, there is nothing to catch
it, and it will cause the process to exit, bringing down the server.
The gpdb::SiMakeStringInfo() wrapper, used in OptVersion(), would translate
any ereport() (e.g. out-of-memory error) into a C++ error, but that's not
what we want in this context. A plain makeStringInfo() would be correct
here, and LibraryVersion() got that right, but for OptVersion it's simpler
to just return a plain string anyway.

Signed-off-by: NXin Zhang <xzhang@pivotal.io>

Some of the functions in funcs.cpp were only used by debugging/testing
code. They were included in the libgpoptudfs.so library, but it was built
in a strange way, from gpAux/Makefile. Move it to a contrib module, along
with the regression tests using it.

This commit leaves only the functions actually used by backend code in
funcs.cpp, and moves the debugging functions only used by the optional
UDFs into the contrib module.

NOTE: The regression tests don't actually work at the moment. But that's not
new, they didn't work before either. I don't have the patience to start
fixing them, so I'm just moving them to the new location in their current
form.

NOTE2: The new module is called orca_debug, but I think some test code
in GPORCA repository expects to find this in libgoptudfs.so. Will need
to fix the scripts there.

A bunch of functions and classes that are not used anywhere.

gporca has a set of banned API calls which needs to be allowed with the
ALLOW_xxx macro in order for gpopt to compile. But it should be the
library caller(GPDB/Orca)'s resposibility to take care of the function call.

see discussions on greenplum-db/gpdb#1136
and https://groups.google.com/a/greenplum.org/forum/#!topic/gpdb-dev/Mcw6JPav6h4

- In ORCA, due to the way exception handled previously we do warning first
and then later print error referring that message. In this commit, we
enhanced the exception handling so we just print a single error message.
- Also, we removed 'PQO unable to generate a plan' or 'Aborting PQO plan
generation' message and make the error message as close as the planner.
- Updated error message with filename and line number from where the exception
is raised.

libgpos has a set of banned API calls which needs to be allowed with
the ALLOW_xxx macro in order for gpopt to compile (and thus run).
The changes to ereport() brought a need for allowing abort() since
it now invokes abort when building with --enable-cassert.

This is a temporary fix awaiting the removal of the banning of
function calls entirely. Pushed even though the CI pipeline failed
to provide a clean run (for seeminly unrelated reasons) due to the
absence of this blocking other efforts.

The old mechanism extracted the version numbers from the Ivy config file,
which doesn't do the right thing if you build without Ivy. Using the
version headers is simpler, anyway.

Without altering functionality, fix a set of compiler warnings in
gpopt: Properly return in non-void function, remove non-function
invocation of variable and use the right formatter for ULLONG when
printing.

Adding functionality to enable retrieving the number of evicted objects from MDCache for testing purposes