Even in SCL world we so far lived fine with --disable-rpath.  But in some
usecases, SCLized libpqwalreceiver.so needs to have RPATH set.

Resolves: rhbz#1550567

diff --git a/src/backend/replication/libpqwalreceiver/Makefile b/src/backend/replication/libpqwalreceiver/Makefile
index a7a5fe1..a9604a1 100644
--- a/src/backend/replication/libpqwalreceiver/Makefile
+++ b/src/backend/replication/libpqwalreceiver/Makefile
@@ -16,6 +16,13 @@ override CPPFLAGS := -I$(srcdir) -I$(libpq_srcdir) $(CPPFLAGS)
 
 OBJS = libpqwalreceiver.o $(WIN32RES)
 SHLIB_LINK = $(libpq) $(filter -lintl, $(LIBS))
+
+# Force rpath to be used even though we disable it everywhere else.  This is
+# needed because the 'libpqwalreceiver.so' is loaded into process (with
+# CREATE SUBSCRIPTION) which has dropped the $LD_LIBRARY_PATH variable from the
+# parent $bindir/postgress process.
+SHLIB_LINK += $(rpath)
+
 SHLIB_PREREQS = submake-libpq
 PGFILEDESC = "libpqwalreceiver - receive WAL during streaming replication"
 NAME = libpqwalreceiver