Fix configure to generate correct expansion of library directory

in pl/plpgsql/src/mklang.sql.

src/configure

@@ -7052,6 +7052,15 @@ fi
 	
 fi
 
+
+test "x$prefix" = xNONE && prefix=$ac_default_prefix
+test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
+
+eval expanded_libdir="$libdir"
+eval expanded_libdir="$expanded_libdir"
+
+
+
 trap '' 1 2 15
 cat > confcache <<\EOF
 # This file is a shell script that caches the results of configure
@@ -7282,6 +7291,7 @@ s%@X_PRE_LIBS@%$X_PRE_LIBS%g
 s%@X_LIBS@%$X_LIBS%g
 s%@X_EXTRA_LIBS@%$X_EXTRA_LIBS%g
 s%@X11_LIBS@%$X11_LIBS%g
+s%@expanded_libdir@%$expanded_libdir%g
 
 CEOF
 EOF