Fix $Id$ vcs keywords.

- Add a new svn-keywords target to fix missing properties;
  - Add a new svn-keywords-check target to locate files lacking $Id$ statement.

Makefile.am

@@ -1,3 +1,4 @@
+# $Id$
 
 ACLOCAL_AMFLAGS = -I m4
 
@@ -25,3 +26,14 @@ clean-local: clean-local-coverage
 .PHONY: clean-local-coverage
 clean-local-coverage:
 	-rm -rf coverage
+
+SVN_KEYWORDS_FILES_LIST_CMD = find $(top_srcdir) -name '*.[hc]' -a ! -name config.h \
+			      -o -name Makefile.am
+svn-keywords:
+	@echo Update files svn:keywords...
+	@$(SVN_KEYWORDS_FILES_LIST_CMD) | xargs svn propset -q svn:keywords Id
+	$(MAKE) svn-keywords-check
+
+svn-keywords-check:
+	@echo Files  missing a '$$Id$$' vcs keyword:
+	@$(SVN_KEYWORDS_FILES_LIST_CMD) | xargs grep -L '\$$Id[^$$]*\$$'

examples/Makefile.am

@@ -1,3 +1,5 @@
+# $Id$
+
 AM_CFLAGS = -I. -I$(top_srcdir)/libfreefare @LIBNFC_CFLAGS@
 AM_LDFLAGS = @LIBNFC_LIBS@
 

libfreefare/Makefile.am

@@ -1,3 +1,4 @@
+# $Id$
 
 AM_CFLAGS = @LIBNFC_CFLAGS@
 AM_LDFLAGS = @LIBNFC_LIBS@