pgsql: Make pqsignal() available to pg_regress of ECPG and isolation su

Make pqsignal() available to pg_regress of ECPG and isolation suites.

Commit 453a5d91d49e4d35054f92785d830df4067e10c1 made it available to the
src/test/regress build of pg_regress, but all pg_regress builds need the
same treatment.  Patch 9.2 through 8.4; in 9.3 and later, pg_regress
gets pqsignal() via libpgport.

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/0ae841a98c21c53901d5bc9a9323a8cc800364f6

Modified Files
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src/interfaces/ecpg/test/Makefile |    4 ++--
src/test/isolation/Makefile       |   12 +++++++-----
2 files changed, 9 insertions(+), 7 deletions(-)