pgsql: Fix configure's incorrect version tests for flex and perl.

Fix configure's incorrect version tests for flex and perl.

awk's equality-comparison operator is "==" not "=". We got this right
in many places, but not in configure's checks for supported version
numbers of flex and perl. It hadn't been noticed because unsupported
versions are so old as to be basically extinct in the wild, and because
the only consequence is whether or not a WARNING flies by during
configure.

Daniel Gustafsson noted the problem with respect to the test for flex,
I found the other by reviewing other awk calls.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/7d7b129277eb545286aecf29ec22b5bb7fdf46bd

Modified Files
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config/perl.m4 | 2 +-
config/programs.m4 | 2 +-
configure | 4 ++--
3 files changed, 4 insertions(+), 4 deletions(-)