pgsql: pg_upgrade: Default new bindir to pg_upgrade location

pg_upgrade: Default new bindir to pg_upgrade location

Make the directory where the pg_upgrade binary resides the default for
new bindir, as running the pg_upgrade binary from where the new
cluster is installed is a very common scenario. Setting this as the
defauly bindir for the new cluster will remove the need to provide it
explicitly via -B in many cases.

To support directories being missing from option parsing, extend the
directory check with a missingOk mode where the path must be filled at
a later point before being used. Also move the exec_path check to
earlier in setup to make sure we know the new cluster bindir when we
scan for required executables.

This removes the exec_path from the OSInfo struct as it is not used
anywhere.

Author: Daniel Gustafsson <daniel(at)yesql(dot)se>
Reviewed-by: Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/9328(dot)1552952117(at)sss(dot)pgh(dot)pa(dot)us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/959f6d6a1821b7d9068244f500dd80953e768d16

Modified Files
--------------
doc/src/sgml/ref/pgupgrade.sgml | 1 +
src/bin/pg_upgrade/option.c | 22 ++++++++++++++--------
src/bin/pg_upgrade/pg_upgrade.c | 28 +++++++++++++++++-----------
src/bin/pg_upgrade/pg_upgrade.h | 1 -
src/bin/pg_upgrade/test.sh | 2 +-
src/tools/msvc/vcregress.pl | 2 +-
6 files changed, 34 insertions(+), 22 deletions(-)