Add .gitignore everywhere based on .cvsignore.

* .gitignore: New.
* build-aux/.gitignore: New.
* data/.gitignore: New.
* doc/.gitignore: New.
* etc/.gitignore: New.
* examples/.gitignore: New.
* examples/calc++/.gitignore: New.
* lib/.gitignore: New.
* m4/.gitignore: New.
* po/.gitignore: New.
* runtime-po/.gitignore: New.
* src/.gitignore: New.
* tests/.gitignore: New.

lib/.gitignore

@@ -0,0 +1,105 @@
+/*.a
+/*.o
+/.deps
+/Makefile
+/Makefile.in
+/argmatch.c
+/argmatch.h
+/basename.c
+/c-ctype.c
+/c-ctype.h
+/c-strcase.h
+/c-strcasecmp.c
+/c-strncasecmp.c
+/charset.alias
+/config.charset
+/config.h
+/config.hin
+/configmake.h
+/dirname.c
+/dirname.h
+/dup-safer.c
+/error.c
+/error.h
+/exitfail.c
+/exitfail.h
+/fd-safer.c
+/fopen-safer.c
+/getopt.c
+/getopt.h
+/getopt.in.h
+/getopt1.c
+/getopt_.h
+/getopt_int.h
+/gettext.h
+/gnulib.mk
+/hash.c
+/hash.h
+/intprops.h
+/inttypes.h
+/inttypes.in.h
+/inttypes_.h
+/localcharset.c
+/localcharset.h
+/malloc.c
+/mbswidth.c
+/mbswidth.h
+/obstack.c
+/obstack.h
+/pipe-safer.c
+/quote.c
+/quote.h
+/quotearg.c
+/quotearg.h
+/ref-add.sed
+/ref-add.sin
+/ref-del.sed
+/ref-del.sin
+/stamp-h1
+/stdbool.h
+/stdbool.in.h
+/stdbool_.h
+/stdint.h
+/stdint.in.h
+/stdint_.h
+/stdio--.h
+/stdio-safer.h
+/stdlib.h
+/stdlib.in.h
+/stdlib_.h
+/stpcpy.c
+/streq.h
+/strerror.c
+/string.h
+/string.in.h
+/string_.h
+/stripslash.c
+/strndup.c
+/strnlen.c
+/strtol.c
+/strtoul.c
+/strverscmp.c
+/strverscmp.h
+/unistd--.h
+/unistd-safer.h
+/unistd.h
+/unistd.in.h
+/unistd_.h
+/unitypes.h
+/uniwidth
+/uniwidth.h
+/unlocked-io.h
+/verify.h
+/wchar.h
+/wchar.in.h
+/wchar_.h
+/wctype.h
+/wctype.in.h
+/wctype_.h
+/wcwidth.c
+/wcwidth.h
+/xalloc-die.c
+/xalloc.h
+/xmalloc.c
+/xstrndup.c
+/xstrndup.h