AUTHORS: Avoid duplicated entries

Instead of simply dumping the list of authors as obtained
from git, we can be a bit smarter and filter out maintainers
so that their names don't appear twice.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>

AUTHORS.in

@@ -90,7 +90,7 @@ Stefan de Konink <dekonink@kinkrsoftware.nl>
 Takahashi Tomohiro <takatom@jp.fujitsu.com>
 Tatsuro Enokura <fj7716hz@aa.jp.fujitsu.com>
 
-#authorslist#
+#contributorslist#
 
 The libvirt logo was designed by Diana Fong
 

Makefile.am

@@ -109,9 +109,17 @@ gen-ChangeLog:
 
 .PHONY: gen-AUTHORS
 gen-AUTHORS:
-	$(AM_V_GEN)if test -d $(srcdir)/.git; then \
-	    out="`cd $(srcdir) && git log --pretty=format:'%aN <%aE>' | sort -u`" && \
-	    perl -p -e "s/#authorslist#// and print '$$out'" \
-	      < $(srcdir)/AUTHORS.in > $(distdir)/AUTHORS-tmp && \
-	    mv -f $(distdir)/AUTHORS-tmp $(distdir)/AUTHORS ; \
+	$(AM_V_GEN)\
+	if test -d $(srcdir)/.git; then \
+	  ( \
+	    cd $(srcdir) && \
+	    git log --pretty=format:'%aN <%aE>' | sort -u \
+	  ) > all.list && \
+	  sort -u $(srcdir)/AUTHORS.in > maint.list && \
+	  comm -23 all.list maint.list > contrib.list && \
+	  contrib="`cat contrib.list`" && \
+	  perl -p -e "s/#contributorslist#// and print '$$contrib'" \
+	    < $(srcdir)/AUTHORS.in > $(distdir)/AUTHORS-tmp && \
+	  mv -f $(distdir)/AUTHORS-tmp $(distdir)/AUTHORS && \
+	  rm -f all.list maint.list contrib.list; \
 	fi