Improve 2012/hamano/try.sh + add helper make rules

The Makefile rules added:

    hint.pdf
    hint

    hello.pdf
    hello

The hint rules generate the hint.pdf (which is the README.md file
obfuscated in a pdf) by feeding the program README.md and then it
compiles hint.pdf as C code. Running it will print the README.md file!

The hello rules generate hello.pdf which is (inside the pdf) an
obfuscated 'Hello World!' program. This is done by a simple echo piped o
the program which redirects it to hello.pdf. Then hello.pdf will be
compiled as C code which when run (as ./hello2) will print 'Hello
World!'.

The script now uses these rules to do what was once done manually. These
rules are .PHONY rules as otherwise they might not always run.

The clobber rule now removes these files.

2012/hamano/try.sh

@@ -15,37 +15,47 @@ make CC="$CC" all >/dev/null || exit 1
 # clear screen after compilation so that only the entry is shown
 clear
 
-read -r -n 1 -p "Press any key to obfuscate README.md, writing to hint.pdf: "
-echo 1>&2
-echo "$ ./hamano < README.md > hint.pdf" 1>&2
-./hamano < README.md > hint.pdf
-
-echo "Now try opening it in a pdf viewer before proceeding." 1>&2
-read -r -n 1 -p "Press any key to continue: "
+# delete hint.pdf
+rm -f hint.pdf
 
+echo "Will obfuscate README.md like:" 1>&2
 echo 1>&2
-echo "$ ${CC} -xc hint.pdf -o hint" 1>&2
-${CC} -xc hint.pdf -o hint
+echo "    ./hamano < README.md > hint.pdf" 1>&2
 echo 1>&2
-read -r -n 1 -p "Press any key to run: ./hint | less (space = next page, q = quit): "
-./hint | less
-
+echo "and then compile it as C like:" 1>&2
+echo 1>&2
+echo "    ${CC} -xc hint.pdf -o hint" 1>&2
+echo 1>&2
+read -r -n 1 -p "Press any key to run: make hint: "
+echo 1>&2
+make hint
+echo 1>&2
+echo "Now try opening hint.pdf in a pdf viewer before proceeding." 1>&2
+echo 1>&2
+read -r -n 1 -p "Press any key to run: ./hint (space = next page, q = quit): "
+echo 1>&2
+./hint | less -rEXFK
 echo 1>&2
 
 echo "Will obfuscate the following code: " 1>&2
 echo 1>&2
-echo "	    int main(){puts("Hello World!");}"
+echo "    int main(){puts("Hello World!");}"
 echo 1>&2
-echo "writing to hello.pdf" 1>&2
-echo 'int main(){puts("Hello World!");}' | ./hamano > hello.pdf
+echo "writing it to hello.pdf via:" 1>&2
 echo 1>&2
-echo "Now open hello.pdf in a pdf viewer before continuing." 1>&2
+echo "     echo 'int main(){puts("Hello World!");}' | ./hamano > hello.pdf"
 echo 1>&2
-read -r -n 1 -p "Press any key to continue to deobfuscate and compile hello.pdf: "
+echo "and then execute the following commands:" 1>&2
 echo 1>&2
-echo "$ ${CC} -Wno-implicit-function-declaration -xc hello.pdf -o hello2" 1>&2
-${CC} -Wno-implicit-function-declaration -xc hello.pdf -o hello2
-echo "$ ./hello2 | ${CC} -Wno-implicit-function-declaration -xc - -o ./hello3" 1>&2
-./hello2 | ${CC} -Wno-implicit-function-declaration -xc - -o ./hello3
-echo "$ ./hello3" 1>&2
-./hello3
+echo "    ${CC} -xc hello.pdf -o hello" 1>&2
+echo "    ./hello | ${CC} -xc - -o hello2" 1>&2
+echo 1>&2
+read -r -n 1 -p "Press any key to run: make hello: "
+echo 1>&2
+make hello
+echo 1>&2
+echo "Now open hello.pdf in a pdf viewer to see the obfuscated source." 1>&2
+echo 1>&2
+read -r -n 1 -p "Press any key to run: ./hello2: "
+echo 1>&2
+./hello2