pgsql: Add opaque declaration of HTAB to tqual.h.

Add opaque declaration of HTAB to tqual.h.

Commit b89e151054a05f0f6d356ca52e3b725dd0505e53 added the
ResolveCminCmaxDuringDecoding declaration to tqual.h, which uses an
HTAB parameter, without declaring HTAB. It accidentally fails to
fail to build with current sources because a declaration happens to
be included, directly or indirectly, in all source files that
currently use tqual.h before tqual.h is first included, but we
shouldn't count on that. Since an opaque declaration is enough
here, just use that, as was done in snapmgr.h.

Backpatch to 9.4, where the HTAB reference was added to tqual.h.

Branch
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REL9_4_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/524e1e40316afc3cf8ba70910fefe1f99b18144f

Modified Files
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src/include/utils/tqual.h | 1 +
1 file changed, 1 insertion(+)