date -I is not portable, on some systems you get the following:
$ date -I
date: option requires an argument -- I
Try `date --help' for more information.
Index: doc/Makefile.am
===================================================================
--- doc/Makefile.am	(revision 931)
+++ doc/Makefile.am	(working copy)
@@ -17,15 +17,15 @@
 # 	mv -f theme.xml.new theme.xml
 
 splashy.1:
-	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date -I` --name "SPLASHY" splashy.pod > splashy.1
+	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date +%Y-%m-%d` --name "SPLASHY" splashy.pod > splashy.1
 splashy_config.1:
-	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date -I` --name "SPLASHY_CONFIG" splashy_config.pod > splashy_config.1
+	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date +%Y-%m-%d` --name "SPLASHY_CONFIG" splashy_config.pod > splashy_config.1
 splashy_update.1:
-	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date -I` --name "SPLASHY_UPDATE" splashy_update.pod > splashy_update.1
+	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date +%Y-%m-%d` --name "SPLASHY_UPDATE" splashy_update.pod > splashy_update.1
 splashy-config.xml.5:
-	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date -I` --name "SPLASHY_UPDATE" splashy-config.xml.pod > splashy-config.xml.5
+	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date +%Y-%m-%d` --name "SPLASHY_UPDATE" splashy-config.xml.pod > splashy-config.xml.5
 splashy-theme.xml.5:
-	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date -I` --name "SPLASHY_UPDATE" splashy-theme.xml.pod > splashy-theme.xml.5
+	pod2man --release 1.0 --section 1 --center "Splashy POSIX boot splash system" --date `date +%Y-%m-%d` --name "SPLASHY_UPDATE" splashy-theme.xml.pod > splashy-theme.xml.5
 
 uninstall-hook:
 	rm -f $(DESTDIR)$(configdir)/config.xml