Improve how to reconfigure coords in 2014/deak

The Makefile now has variables so that one can do something like

    make X1=-1 Y2=-1 clobber alt

or whatever, with the variables X1, X2, Y1 and Y2 set to what the author
originally had it as.

The alt code still has #ifndef..#endif so that one can (if they want to
be silly) compile it without make(1).

2014/deak/try.alt.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+#
+# try.alt.sh - demonstrate IOCCC winner 2014/deak alt code
+#
+
+# make sure CC is set so that when we do make CC="$CC" it isn't empty. Doing it
+# this way allows us to have the user specify a different compiler in an easy
+# way.
+if [[ -z "$CC" ]]; then
+    CC="cc"
+fi
+
+# compile the alt code with various parameters and run it to show different
+# output
+
+read -r -n 1 -p "Press any key to change X1 to 2, X2 to -1 and Y1 to -2.3: "
+echo 1>&2
+make -B X1=2 X2=-1 Y1=-2.3 alt >/dev/null || exit
+read -r -n 1 -p "Press any key to continue (space = next page, q = quit): "
+echo 1>&2
+./prog.alt | less -EXF
+
+read -r -n 1 -p "Press any key to change X1 to 3, X2 to -2 and Y1 to -3.3: "
+echo 1>&2
+make -B X1=3 X2=-2 Y1=-3.3 alt >/dev/null || exit
+read -r -n 1 -p "Press any key to continue (space = next page, q = quit): "
+echo 1>&2
+./prog.alt | less -EXF
+
+read -r -n 1 -p "Press any key to change X1 to 1, X2 to -1 and Y1 to -0.3: "
+echo 1>&2
+make -B X1=1 X2=-1 Y1=-0.3 alt >/dev/null || exit
+read -r -n 1 -p "Press any key to continue (space = next page, q = quit): "
+echo 1>&2
+./prog.alt | less -EXF
+
+read -r -n 1 -p "Press any key to change X1 to 1, X2 to -1, Y1 to -0.3 and Y2 to -1.3: "
+echo 1>&2
+make -B X1=1 X2=-1 Y1=-0.3 Y2=-1.3 alt >/dev/null || exit
+read -r -n 1 -p "Press any key to continue (space = next page, q = quit): "
+echo 1>&2
+./prog.alt | less -EXF
+
+read -r -n 1 -p "Press any key to try the original configuration: "
+echo 1>&2
+make clobber alt >/dev/null || exit 1
+read -r -n 1 -p "Press any key to continue (space = next page, q = quit): "
+echo 1>&2
+./prog.alt