"clang: error: cannot specify -o when generating multiple output files" fix - c

Question

I'm trying to compile my C project using clang (I'm on MacOS Monterry) and a Makefile, but I keep getting the same error from clang in the command line:
> make
gcc -c src/ji.c src/main.c -o src/ji.o
clang: error: cannot specify -o when generating multiple output files
make: *** [src/ji.o] Error 1
These are the only files I have in the project so far:
src/main.c
src/ji.c
include/ji.h
The Makefile looks like this:
cc = gcc
src = $(wildcard src/*.c)
obj = $(src:.c=.o)
exec = ji
$(exec): $(obj)
$(cc) -Iinclude $< -o build/$#
%.o: %.c
$(cc) -c $(src) -o $#
clean:
-rm src/*.o
-rm ji
From YouTube videos I've seen, this should be the ideal Makefile for the project but no matter what I change I get the error.

Answer 1

There are a few issues:
-Iinclude needs to be on the %.o: %.c rule command
In %.o: %.c, we don't want $(src) but rather $<
We want patsubst to get the .o list obj
The $(exec) target doesn't match the -o option
The clean doesn't match the placement of the executable
Here's a refactored version (e.g. one way to do this--there are others):
cc = gcc
src = $(wildcard src/*.c)
obj = $(patsubst %.c,%.o,$(src))
exec = build/ji
$(exec): $(obj)
mkdir -p build
$(cc) $^ -o $#
%.o: %.c
$(cc) -c $< -o $# -Iinclude
clean:
rm -f src/*.o
rm -fr build
Here's the output of make:
gcc -c src/ji.c -o src/ji.o -Iinclude
gcc -c src/main.c -o src/main.o -Iinclude
mkdir -p build
gcc src/ji.o src/main.o -o build/ji
Here's the output of make clean:
rm -f src/*.o
rm -fr build