merged rpn(1); closes #2

Makefile

@@ -9,6 +9,7 @@
 
 .POSIX:
 .PRAGMA: posix_202x # future POSIX standard support à la pdpmake(1)
+.PRAGMA: command_comment # breaks without this?
 
 PREFIX=/usr/local
 
@@ -51,7 +52,7 @@ build/o/libsysexits.rlib: build
 		"$$(printf '#include <sysexits.h>\n' \
 			| cpp -M -idirafter "build/include" - \
 			| sed 's/ /\n/g' | grep sysexits.h)" \
-		| $(RUSTC) $(RUSTCFLAGS) --crate-type lib -o build/o/libsysexits.rlib -
+		| $(RUSTC) $(RUSTFLAGS) --crate-type lib -o build/o/libsysexits.rlib -
 
 build/o/libgetopt.rlib: src/getopt-rs/lib.rs
 	$(RUSTC) $(RUSTCFLAGS) --crate-type=lib --crate-name=getopt \
@@ -79,6 +80,13 @@ intcmp: build/bin/intcmp
 build/bin/intcmp: src/intcmp.c build
 	$(CC) $(CFLAGS) -o $@ src/intcmp.c
 
+.PHONY: rpn
+rpn: build/bin/rpn
+build/bin/rpn: src/rpn.rs build build/o/libsysexits.rlib
+	$(RUSTC) $(RUSTFLAGS) \
+		--extern sysexits=build/o/libsysexits.rlib \
+		-o $@ src/rpn.rs
+
 .PHONY: scrut
 scrut: build/bin/scrut
 build/bin/scrut: src/scrut.c build