Makefile: fix PHONYness of existing recipes and make non-PHONY recipes

Makefile

@@ -1,5 +1,5 @@
 # Copyright (c) 2023–2024 Emma Tebibyte <emma@tebibyte.media>
-# Copyright (c) 2023 DTB <trinity@trinity.moe>
+# Copyright (c) 2023–2024 DTB <trinity@trinity.moe>
 # Copyright (c) 2023 Sasha Koshka <sashakoshka@tebibyte.media>
 # SPDX-License-Identifier: FSFAP
 #
@@ -60,27 +60,43 @@ libgetopt: src/getopt-rs/lib.rs
 	$(RUSTC) $(RUSTCFLAGS) --crate-type=lib --crate-name=getopt \
 		-o build/o/libgetopt.rlib src/getopt-rs/lib.rs
 
-dj: src/dj.c build
-	$(CC) $(CFLAGS) -o build/bin/dj src/dj.c
+.PHONY: dj
+dj: build/bin/dj
+build/bin/dj: src/dj.c build
+	$(CC) $(CFLAGS) -o $@ src/dj.c
 
-false: src/false.c build
-	$(CC) $(CFLAGS) -o build/bin/false src/false.c
+.PHONY: false
+false: build/bin/false
+build/bin/false: src/false.c build
+	$(CC) $(CFLAGS) -o $@ src/false.c
 
-fop: src/fop.rs build libgetopt sysexits
+.PHONY: fop
+fop: build/bin/fop
+build/bin/fop: src/fop.rs build libgetopt sysexits
 	$(RUSTC) $(RUSTFLAGS) --extern getopt=build/o/libgetopt.rlib \
-		-o build/bin/fop src/fop.rs
+		-o $@ src/fop.rs
 
-intcmp: src/intcmp.c build
-	$(CC) $(CFLAGS) -o build/bin/intcmp src/intcmp.c
+.PHONY: intcmp
+intcmp: build/bin/intcmp
+build/bin/intcmp: src/intcmp.c build
+	$(CC) $(CFLAGS) -o $@ src/intcmp.c
 
-scrut: src/scrut.c build
-	$(CC) $(CFLAGS) -o build/bin/scrut src/scrut.c
+.PHONY: scrut
+scrut: build/bin/scrut
+build/bin/scrut: src/scrut.c build
+	$(CC) $(CFLAGS) -o $@ src/scrut.c
 
-str: src/str.c build
-	$(CC) $(CFLAGS) -o build/bin/str src/str.c
+.PHONY: str
+str: build/bin/str
+build/bin/str: src/str.c build
+	$(CC) $(CFLAGS) -o $@ src/str.c
 
-strcmp: src/strcmp.c build
-	$(CC) $(CFLAGS) -o build/bin/strcmp src/strcmp.c
+.PHONY: strcmp
+strcmp: build/bin/strcmp
+build/bin/strcmp: src/strcmp.c build
+	$(CC) $(CFLAGS) -o $@ src/strcmp.c
 
-true: src/true.c build
-	$(CC) $(CFLAGS) -o build/bin/true src/true.c
+.PHONY: true
+true: build/bin/true
+build/bin/true: src/true.c build
+	$(CC) $(CFLAGS) -o $@ src/true.c