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/Makefile

@@ -40,7 +40,7 @@ include ../../var.mk
 #
 CSILENCE= -Wno-bitwise-op-parentheses -Wno-empty-body -Wno-format \
 	-Wno-format-security -Wno-gnu-zero-variadic-macro-arguments -Wno-main \
-	-Wno-parentheses
+	-Wno-parentheses -Wno-implicit-function-declaration -Wno-strict-prototypes
 
 # Common C compiler warning flags
 #
@@ -129,11 +129,48 @@ all: data ${TARGET}
 .PHONY: all alt data everything diff_orig_prog diff_prog_orig \
 	diff_alt_prog diff_prog_alt diff_orig_alt diff_alt_orig \
 	clean clobber install love haste waste maker easter_egg \
-	sandwich supernova deep_magic magic charon pluto
+	sandwich supernova deep_magic magic charon pluto hint hint.pdf \
+	hello hello.pdf
+
 
 ${PROG}: ${PROG}.c
 	${CC} ${CFLAGS} $< -o $@ ${LDFLAGS}
 
+# hint.pdf rules to simplify use of 2012/hamano
+#
+
+# This rule generates the hint.pdf file which is the README.md obfuscated as a
+# PDF that is NOT part of the repo:
+hint.pdf: ${PROG} README.md
+	./${PROG} < README.md > hint.pdf
+	@echo
+
+# This rule, hint, depends on the hint.pdf rule. That rule generates the
+# hint.pdf file (NOT part of the repo) which is an obfuscated (as a PDF) version
+# of the README.md. This rule, in turn, COMPILES THAT PDF FILE AS C CODE!
+hint: hint.pdf
+	${CC} ${CFLAGS} -xc $< -o $@
+
+
+# hello.pdf rules to simplify use of 2012/hamano
+#
+
+# This rule generates the hello.pdf file which is a simple 'Hello World!'
+# program obfuscated as a PDF:
+hello.pdf:
+	echo 'int main(){puts("Hello World!");}' | ./${PROG} > hello.pdf
+
+# This rule, hello, depends on the hello.pdf rule. That rule generates the
+# hello.pdf file (NOT part of the repo) which is an obfuscated (as a PDF) version
+# of a simple 'Hello World!' program. This rule, in turn, COMPILES THAT PDF FILE
+# AS C CODE to hello and then pipes it to cc to compile it to hello2 which when
+# run will print 'Hello World!'.
+hello: hello.pdf
+	@echo
+	${CC} ${CFLAGS} -xc hello.pdf -o $@
+	@echo
+	./hello | ${CC} ${CFLAGS} -xc - -o hello2 
+
 # alternative executable
 #
 alt: data ${ALT_TARGET}
@@ -204,7 +241,7 @@ clean:
 	fi
 
 clobber: clean
-	${RM} -f ${TARGET} ${ALT_TARGET}
+	${RM} -f ${TARGET} ${ALT_TARGET} hint.pdf hello.pdf hello hello2
 	${RM} -rf *.dSYM
 	@-if [ -e sandwich ]; then \
 	    ${RM} -f sandwich; \