pgsql: Make ecpg's rjulmdy() and rmdyjul() agree with their declaration

Make ecpg's rjulmdy() and rmdyjul() agree with their declarations.

We had "short *mdy" in the extern declarations, but "short mdy[3]"
in the actual function definitions.  Per C99 these are equivalent,
but recent versions of gcc have started to issue warnings about
the inconsistency.  Clean it up before the warnings get any more
widespread.

Back-patch, in case anyone wants to build older PG versions with
bleeding-edge compilers.

Discussion: https://postgr.es/m/2401575.1611764534@sss.pgh.pa.us

Branch
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REL9_5_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/27c79a46aae34e239c5655586bd6be9102469853

Modified Files
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src/interfaces/ecpg/compatlib/informix.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)