Convert cvsignore to gitignore, and add .gitignore for build targets.

src/bin/pg_ctl/.gitignore

+/pg_ctl

src/bin/pg_dump/.gitignore

+/kwlookup.c
+
+/pg_dump
+/pg_dumpall
+/pg_restore

src/bin/pg_resetxlog/.gitignore

+/pg_crc.c
+
+/pg_resetxlog

src/bin/psql/.cvsignore

-psqlscan.c
-sql_help.h
-sql_help.c

src/bin/psql/.gitignore

+/psqlscan.c
+/sql_help.h
+/sql_help.c
+/dumputils.c
+/keywords.c
+/kwlookup.c
+
+/psql

src/bin/scripts/.gitignore

+/clusterdb
+/createdb
+/createlang
+/createuser
+/dropdb
+/droplang
+/dropuser
+/reindexdb
+/vacuumdb
+
+/dumputils.c
+/keywords.c
+/kwlookup.c
+/mbprint.c
+/print.c

src/include/.gitignore

+/stamp-h
+/pg_config.h
+/pg_config_os.h
+/dynloader.h
+

src/include/catalog/.gitignore

+/schemapg.h

src/include/parser/.gitignore

+/gram.h

src/include/utils/.gitignore

+/fmgroids.h
+/probes.h

src/interfaces/ecpg/compatlib/.cvsignore

-libecpg_compatdll.def
-libecpg_compatddll.def
-blibecpg_compatdll.def

src/interfaces/ecpg/compatlib/.gitignore

+/libecpg_compatdll.def
+/libecpg_compatddll.def
+/blibecpg_compatdll.def
+/exports.list

src/interfaces/ecpg/ecpglib/.cvsignore

-libecpgdll.def
-libecpgddll.def
-blibecpgdll.def

src/interfaces/ecpg/ecpglib/.gitignore

+/libecpgdll.def
+/libecpgddll.def
+/blibecpgdll.def
+/exports.list
+
+/path.c
+/pgstrcasecmp.c
+/strlcpy.c
+/thread.c

src/interfaces/ecpg/include/.gitignore

+/ecpg_config.h
+/stamp-h

src/interfaces/ecpg/pgtypeslib/.cvsignore

-libpgtypesdll.def
-libpgtypesddll.def
-blibpgtypesdll.def

src/interfaces/ecpg/pgtypeslib/.gitignore

+/libpgtypesdll.def
+/libpgtypesddll.def
+/blibpgtypesdll.def
+/exports.list
+
+/pgstrcasecmp.c

src/interfaces/ecpg/preproc/.cvsignore

-preproc.y
-preproc.c
-preproc.h
-pgc.c

src/interfaces/ecpg/preproc/.gitignore

+/preproc.y
+/preproc.c
+/preproc.h
+/pgc.c
+
+/ecpg
+/kwlookup.c

src/interfaces/libpq/.cvsignore

-libpqdll.def
-libpqddll.def
-blibpqdll.def
-libpq-dist.rc