HOWTO: Build tweaks for macOS and FreeBSD

[modest]

Putting this into a PR would require some opinions about the right way to handle multi-platform. So I'll just share the build steps that seemed necessary to get this to compile on macOS and FreeBSD.

(My FreeBSD target was a router running pfSense, a gateway/firewall.)

macOS

macOS only needs Makefile changes.

./src/Makefile

PROGNAME = repeater
SRC = repeater.c parseconfig.c json.c

OBJS = $(patsubst %.c,%.o,$(SRC))

CC = gcc
CFLAGS = -Wall -Werror -std=c99 -I../include -D_POSIX_SOURCE

build-release: $(OBJS)
        echo "$(OBJS)"
        mkdir -p ../bin
        $(CC) $(CFLAGS) -o ../bin/$(PROGNAME) $(OBJS) -lm

build-debug: CFLAGS += -g -DDEBUG
build-debug: $(OBJS)
        mkdir -p ../bin
        $(CC) $(CFLAGS) -o ../bin/$(PROGNAME) $(OBJS) -lm

%.o: %.c ../include/%.h
        $(CC) $(CFLAGS) -c $<

clean:
        rm -f ./*.o
        rm -rf ../bin

• macOS gcc (which is really clang) takes -pedantic more seriously than gcc and had complaints, so that argument is removed.
• clang also didn't like -lm being used in the initial compile, so it's been removed there (but remains in linking)

FreeBSD

FreeBSD needs Makefile tweaks and adding a couple of missing headers.

./src/Makefile

PROGNAME = repeater
SRC = repeater.c parseconfig.c json.c
OBJS = repeater.o parseconfig.o json.o

CC = cc
CFLAGS = -Wall -Werror -std=c99 -pedantic -I../include -D_POSIX_SOURCE

build-release: $(OBJS)
        mkdir -p ../bin
        $(CC) $(CFLAGS) -o ../bin/$(PROGNAME) $(OBJS) -lm

build-debug: CFLAGS += -g -DDEBUG
build-debug: $(OBJS)
        mkdir -p ../bin
        $(CC) $(CFLAGS) -o ../bin/$(PROGNAME) $(OBJS) -lm

%.o: %.c ../include/%.h
        $(CC) $(CFLAGS) -c $< -lm

clean:
        rm -f ./*.o
        rm -rf ../bin

• CC set to cc for FreeBSD
• OBJS changed to an string list instead of being generated. BSD make didn't like the patsubst, and didn't bother trying to find out why.

./src/repeater.c

Needs these headers added:

#include <sys/socket.h>
#include <netinet/in.h>

./src/parseconfig.c

Needs this header added:

#include <sys/socket.h>