build: Don't remove adu.png on make clean.

This was appropriate with the old logo which was generated from a
.sk source file. The new logo, however, only exists in png format,
so we should never remove it.

The adu.sk~ file can also be skipped from the list of files to be
removed by make clean.

diff --git a/Makefile b/Makefile
index 00ef9e84c27d9eaec5312792fee98ccbe8be32d1..58202a224a6634ed39288ccf3b44f263ee715fb7 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -72,7 +72,7 @@ adu.1: adu adu.1.inc
        man2html $< | sed -e 's|^<DT><DD>$$|<DT><DD><br>|g' > $@
 
 clean:
-       rm -f *.o adu *cmdline.c *cmdline.h adu.1 adu.1.html adu.png index.html adu.sk~
+       rm -f *.o adu *cmdline.c *cmdline.h adu.1 adu.1.html index.html
 
 index.html: adu.1.html index.html.in INSTALL README
        sed -e '/@README@/,$$d' index.html.in > $@