Add .gitignore to m4/ and po/ directories

Instead of trying to keep up with files added by Gettext tools and
Autotools, maintain a list of tracked files in those directories.

(cherry picked from commit 5932466)

Author: N0NB

.gitignore

@@ -1,3 +1,4 @@
+# include/, m4/, and po/ all have their own .gitignore
 *~
 ABOUT-NLS
 Makefile
@@ -8,64 +9,6 @@ build-aux/
 config.log
 config.status
 configure
-m4/Makefile
-m4/Makefile.in
-m4/codeset.m4
-m4/fcntl-o.m4
-m4/gettext.m4
-m4/glibc2.m4
-m4/glibc21.m4
-m4/iconv.m4
-m4/intdiv0.m4
-m4/intl.m4
-m4/intldir.m4
-m4/intlmacosx.m4
-m4/intmax.m4
-m4/inttypes-pri.m4
-m4/inttypes_h.m4
-m4/lcmessage.m4
-m4/lib-ld.m4
-m4/lib-link.m4
-m4/lib-prefix.m4
-m4/lock.m4
-m4/longlong.m4
-m4/nls.m4
-m4/po.m4
-m4/printf-posix.m4
-m4/progtest.m4
-m4/size_max.m4
-m4/stdint_h.m4
-m4/threadlib.m4
-m4/uintmax_t.m4
-m4/visibility.m4
-m4/wchar_t.m4
-m4/wint_t.m4
-m4/xsize.m4
-po/Makefile
-po/Makefile.in
-po/Makefile.in.in
-po/Makevars.template
-po/POTFILES
-po/Rules-quot
-po/boldquot.sed
-po/de.gmo
-po/[email protected]
-po/[email protected]
-po/[email protected]
-po/[email protected]
-po/[email protected]
-po/[email protected]
-po/[email protected]
-po/[email protected]
-po/es.gmo
-po/fr.gmo
-po/insert-header.sin
-po/nl.gmo
-po/pl.gmo
-po/pt.gmo
-po/quot.sed
-po/remove-potcdate.sin
-po/stamp-po
 src/.deps/
 src/Makefile
 src/Makefile.in

m4/.gitignore

@@ -0,0 +1,7 @@
+# Ignore everything in this directory
+*
+# Except these files (be sure files to be tracked are added here!)
+!.gitignore
+!ax_append_flag.m4
+!ax_cflags_warn_all.m4
+!Makefile.am

po/.gitignore

@@ -0,0 +1,14 @@
+# Ignore everything in this directory
+*
+# Except these files (be sure files to be tracked are added here!)
+!.gitignore
+!LINGUAS
+!Makevars
+!POTFILES.in
+!de.po
+!es.po
+!fr.po
+!nl.po
+!pl.po
+!pt.po
+!xdx.pot