pgsql: Hide a static inline from FRONTEND code.

Hide a static inline from FRONTEND code.

For some reason pg_waldump is including tuptable.h, and the recent
addition of a static inline function to it is causing problems on
older buildfarm members that fail to optimize such functions away
completely.  I wonder if this situation doesn't mean that some header
refactoring is called for ... but as a band-aid, wrap the static
function in "#ifndef FRONTEND".

Discussion: https://postgr.es/m/20180824154237.mabsv6fsz5q37bma@alap3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/14ea36520389dbb1b48524223cf09389154a0f2e

Modified Files
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src/include/executor/tuptable.h | 4 ++++
1 file changed, 4 insertions(+)