Add unobfuscated alt code to 2020/otterness

This code was found on the author's web page about the entry and has
been added as prog.alt.c. I added the try.alt.sh script as well.

Manifest updated and rebuilt .entry.json and index.html files.

2020/otterness/Makefile

@@ -115,8 +115,8 @@ OBJ= ${PROG}.o
 DATA=
 TARGET= ${PROG}
 #
-ALT_OBJ=
-ALT_TARGET=
+ALT_OBJ= ${PROG}.alt.o
+ALT_TARGET= ${PROG}.alt
 
 
 #################
@@ -139,6 +139,9 @@ ${PROG}: ${PROG}.c
 alt: data ${ALT_TARGET}
 	@${TRUE}
 
+${PROG}.alt: ${PROG}.alt.c
+	${CC} ${CFLAGS} $< -o $@ ${LDFLAGS}
+
 # data files
 #
 data: ${DATA}