Rework the Makefile a bit

Makefile

@@ -1,20 +1,21 @@
-include config.mk
+.POSIX:
 
-.PHONY: all clean install test
+include config.mk
 
 all: scroll
+
 clean:
 	rm -f scroll ptty
 
 config.h:
 	cp config.def.h config.h
 
-scroll: scroll.c config.h
-	$(CC) $(CFLAGS) $(CPPFLAGS) scroll.c $(LDLIBS) -o $@
+scroll: config.h
 
 install: scroll
-	cp scroll ${BINDIR}
-	cp scroll.1 ${MAN1DIR}
+	mkdir -p $(BINDIR) $(MANDIR)/man1
+	cp -f scroll $(BINDIR)
+	cp -f scroll.1 $(MANDIR)/man1
 
 test: scroll ptty
 	# check usage
@@ -22,3 +23,8 @@ test: scroll ptty
 	# check exit passthrough of child
 	if ! ./ptty ./scroll true;  then exit 1; fi
 	if   ./ptty ./scroll false; then exit 1; fi
+
+.c:
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -o $@ $< -lutil
+
+.PHONY: all clean install test

config.mk

@@ -1,10 +1,9 @@
 # paths
 PREFIX	= /usr/local
-BINDIR	= ${PREFIX}/bin
-MANDIR	= ${PREFIX}/share/man
-MAN1DIR	= ${MANDIR}/man1
+BINDIR	= $(PREFIX)/bin
+MANDIR	= $(PREFIX)/share/man
 
-CC ?= cc
-CFLAGS = -std=c99 -pedantic -Wall -Wextra -g
-LDLIBS += -lutil
-CPPFLAGS += -D_DEFAULT_SOURCE
+CPPFLAGS = -D_DEFAULT_SOURCE
+# if your system is not POSIX, add -std=c99 to CFLAGS
+CFLAGS = -Os
+LDFLAGS = -s