Makefile: move PHONYs to their respective recipes

Makefile

@@ -10,11 +10,6 @@
 .POSIX:
 .PRAGMA: posix_202x # future POSIX standard support à la pdpmake(1)
 
-.PHONY: all
-.PHONY: clean
-.PHONY: install
-.PHONY: test
-
 PREFIX=/usr/local
 
 CC=cc
@@ -23,6 +18,7 @@ RUSTC=rustc
 # to build, first run ./configure
 include *.mk
 
+.PHONY: all
 all: dj false fop intcmp scrut str strcmp true
 
 build:
@@ -30,6 +26,7 @@ build:
 	# https://github.com/rust-lang/rust-bindgen/issues/2703
 	mkdir -p build/bin build/include build/lib build/o build/test
 
+.PHONY: clean
 clean:
 	rm -rf build/ dist/
 
@@ -38,10 +35,12 @@ dist: all
 	cp build/bin/* dist/bin/
 	cp docs/*.1 dist/share/man/man1/
 
+.PHONY: install
 install: dist
 	mkdir -p $(PREFIX)
 	cp -r dist/* $(PREFIX)/
 
+.PHONY: test
 test: build
 	tests/cc-compat.sh
 	tests/posix-compat.sh