pgsql: Add PG_TEST_EXTRA configure option to the Make builds

Add PG_TEST_EXTRA configure option to the Make builds

The Meson builds have PG_TEST_EXTRA as a configure-time variable,
which was not available in the Make builds. To ensure both build
systems are in sync, PG_TEST_EXTRA is now added as a configure-time
variable. It can be set like this:

    ./configure PG_TEST_EXTRA="kerberos, ssl, ..."

Note that to preserve the old behavior, this configure-time variable
is overridden by the PG_TEST_EXTRA environment variable when you run
the tests.

Author: Jacob Champion
Reviewed by: Ashutosh Bapat, Nazir Bilal Yavuz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/99b937a44f087c133c4db42e1bf4a8990ea417b9

Modified Files
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configure              |  6 ++++++
configure.ac           |  2 ++
src/Makefile.global.in | 10 ++++++++++
src/test/Makefile      |  5 -----
4 files changed, 18 insertions(+), 5 deletions(-)