pgsql: Temporarily add some information about python include paths to c

Temporarily add some information about python include paths to configure.

We're still (see e0e567a1067, e0e567a1067) working on replacing use of the
deprecated distutils. This commit just makes configure print out the results
of different ways of determining the include path. Hopefully this will help us
to find a way to transition away from distutils without turning the buildfarm
red for prolonged amounts of time.

Discussion: https://postgr.es/m/20220124025301.qu36x44w6m67cnap@alap3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/f032f63e727c1ab07603b3d1cd88d50f850d5738

Modified Files
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config/python.m4 | 21 +++++++++++++++++++++
configure        | 23 +++++++++++++++++++++++
2 files changed, 44 insertions(+)