Some more gitignore cleanups: cover contrib and PL regression test outputs.

Also do some further work in the back branches, where quite a bit wasn't
covered by Magnus' original back-patch.

contrib/btree_gist/.gitignore

@@ -1 +1,3 @@
 /btree_gist.sql
+# Generated subdirectories
+/results/

contrib/cube/.gitignore

@@ -1,3 +1,6 @@
 /cubeparse.c
+/cubeparse.h
 /cubescan.c
 /cube.sql
+# Generated subdirectories
+/results/

contrib/dblink/.gitignore

@@ -1 +1,3 @@
 /dblink.sql
+# Generated subdirectories
+/results/

contrib/earthdistance/.gitignore

@@ -1 +1,3 @@
 /earthdistance.sql
+# Generated subdirectories
+/results/

contrib/hstore/.gitignore

@@ -1 +1,3 @@
 /hstore.sql
+# Generated subdirectories
+/results/

contrib/intagg/.gitignore

@@ -0,0 +1 @@
+/int_aggregate.sql

contrib/intarray/.gitignore

@@ -1 +1,3 @@
 /_int.sql
+# Generated subdirectories
+/results/

contrib/ltree/.gitignore

@@ -1 +1,3 @@
 /ltree.sql
+# Generated subdirectories
+/results/

contrib/pg_trgm/.gitignore

@@ -1 +1,3 @@
 /pg_trgm.sql
+# Generated subdirectories
+/results/

contrib/pgcrypto/.gitignore

@@ -1 +1,3 @@
 /pgcrypto.sql
+# Generated subdirectories
+/results/

contrib/seg/.gitignore

@@ -1,3 +1,6 @@
 /segparse.c
+/segparse.h
 /segscan.c
 /seg.sql
+# Generated subdirectories
+/results/

contrib/tablefunc/.gitignore

@@ -1 +1,3 @@
 /tablefunc.sql
+# Generated subdirectories
+/results/

contrib/tsearch2/.gitignore

@@ -1 +1,4 @@
 /tsearch2.sql
+/uninstall_tsearch2.sql
+# Generated subdirectories
+/results/

contrib/xml2/.gitignore

@@ -0,0 +1,2 @@
+# Generated subdirectories
+/results/