* Enable PXF by default for GPDB builds

* Disable pxf wherever libcurl is disabled

- instead of trying to keep GPDB readme in sync with GPORCA readme, just refer to it

- fixes cd path
- removes macOS warning that is not currently an issue
- treats comment like other readme comments

- Move Conan instructions above manual orca setup instructions
  so that people don't do manual work first (like we did).
- Inline recommendation to parallelize make with -j8.
- Fix formatting of code blocks in README.md

See issues:
 - https://github.com/greenplum-db/gpdb/issues/3178
 - https://github.com/greenplum-db/gpdb/pull/3332

* Use built-in JSON parser for PXF fragments

Instead of relying on a external library, use the built-in JSON
parser in the backend for the PXF fragments parsing. Since this
replaces the current implementation with an event-based callback
parser, the code is more complicated, but dogfooding the parser
that we want extension writers to use is a good thing.

This removes the dependency on json-c from autoconf, and enables
building PXF on Travis for extra coverage.

* Use elog for internal errors, and ereport for user errors

Internal errors where we are interested in source filename should
use elog() which will decorate the error messages automatically
with this information. The connection error is interesting for the
user however, use ereport() instead there.

Add required steps before building GPDB on centos.
Fixes issue #2715, #2995 and #3163.

[ci skip]

The README was still referencing gp-xerces even though it's no
longer required for ORCA, so this was removed. On top of that,
some Markdown formatting fixes, minor wordsmithing, typo fixes
as well as some whitespace cleanup and turned URLs into links.

This makes the linux directions look more like the macOS directions for the top level readme.

* README updates for PXF setup instructions

* PXF README updates for PXF setup instructions

* test update

* README updates for PXF setup instructions

* PXF README updates for PXF setup instructions

* note on curl depedancy

* minor update

* Change the directory location and update readme

When conan is used to build the dependencies (orca & xerces) of gpdb, it
copies the headers and libraries to the path specified in
the imports section of the conanfile.txt.
Changing the target copy location to /usr/local/include and
/usr/local/lib as its the default for gpdb. In case the user
prefers to have a different directory, they can change the location
accordingly.

Signed-off-by: NJohn Gaskin <johntgaskin@gmail.com>
Signed-off-by: NTodd Sedano <tsedano@pivotal.io>

- Currently the readme leaves out the  dependency
- Places all dependencies into one location in the readme

- make distclean can not be called before configure

Signed-off-by: NChris Hajas <chajas@pivotal.io>

Partially addresses https://github.com/greenplum-db/gpdb/issues/2422Signed-off-by: NTodd Sedano <professor@gmail.com>
Signed-off-by: NChris Hajas <chajas@pivotal.io>

* Include instructions to build optimizer now that it's default [#145362679]

Follow on to #2495

* Update documentation to reflect new test target:
"make installcheck-good" -> "make installcheck-world"

- gpperfmon tracks a variety of queries and statistics and system
  properties and metrics in a dedicated database
- Until recently, it hadn't been tested or built very reliably here. It
  is now part of the gpdb_master pipeline.
- We are doing a lot of work to revitalize and provide tests for this
  feature; we plan to make many upcoming pull requests for this
  feature in different ways
- We will look into testing this with installcheck, but for now, it is
  tested with Behave
- Building it as part of PRs will help us get faster feedback
- This should add negligible time to compilation: the tests themselves
  run in less than 5 minutes typically, and will be running in parallel
  with ICW
Signed-off-by: NMarbin Tan <mtan@pivotal.io>

Set the correct Wiki URL to use for the project, we have moved over
to using the Github wiki on the main repo and not the wiki on the
website repo.

Remove references to Pivotal Greenplum documentation in the README
and stick to greenplum.orc/docs/ there as those are the applicable
docs.  While there update the README.md to actually match reality,
the docs are now in the main repo.

With the last remaining testsuites moved over to ICW, there is no
longer anything left running in BugBuster. Remove the remaining
files and BugBuster makefile integration in one big swing of the
git rm axe. The only thing left in use was a data file which was
referenced from ICW, move this to regress/data instead.

Signed-off-by: NC.J. Jameson <cjameson@pivotal.io>

The GPOS library has been imported into the GPORCA repository so
there is no need to install it separately anymore.