Add config.mk and Linux support.

Makefile

@@ -1,6 +1,14 @@
-# pointtools
 # See LICENSE for license details.
-PREFIX=	/usr/local
+
+include config.mk
+
+all: options bin/md2point
+
+options:
+	@echo pointtools build options:
+	@echo "CFLAGS   = ${CFLAGS}"
+	@echo "LDFLAGS  = ${LDFLAGS}"
+	@echo "CC       = ${CC}"
 
 bin/md2point: md2point.o
 	${CC} -o $@ md2point.o ${LDFLAGS}
@@ -12,16 +20,16 @@ install:
 	install -m755 bin/dir2point $(PREFIX)/bin/dir2point
 	install -m755 bin/md2point  $(PREFIX)/bin/md2point
 	install -m755 bin/point2pdf $(PREFIX)/bin/point2pdf
-	install -m644 md2point.1    $(PREFIX)/share/man/man1/md2point.1
+	install -m644 md2point.1    $(MANPREFIX)/man1/md2point.1
 
 uninstall:
 	rm -f $(PREFIX)/bin/dir2point
 	rm -f $(PREFIX)/bin/md2point
 	rm -f $(PREFIX)/bin/point2pdf
-	rm -f $(PREFIX)/share/man/man1/md2point.1
+	rm -f $(MANPREFIX)/man1/md2point.1
 
 clean:
 	rm -f bin/md2point
 	rm -f md2point.o
 
-.PHONY: install uninstall clean
+.PHONY: all options install uninstall clean

md2point.c

@@ -1,3 +1,7 @@
+/*
+ * See LICENSE for license details.
+ */
+#include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <err.h>