Did a Mac update ruin my ability to use gcc? - c

Question

I am trying to compile two c files into one executable. In the directory I have only three files; Makefile, main.c and myfunction.c.
Makefile:
CC = gcc
CFLAGS = -Wall -g -O0
LIBS = -lm
SRCS = $(wildcard *.c)
OBJS = $(SRCS:.c=.o)
MAIN = main
all: $(MAIN)
#echo Program has been compiled
$(MAIN): $(OBJS)
$(CC) $(CFLAGS) $(INCLUDES) -o $(MAIN) $(OBJS) $(LIBS)
clean:
$(RM) *.o *~ $(MAIN)
main.c:
#include <stdio.h>
void myfunc();
int main (int argc, char *argv[]) {
myfunc();
return 0;
}
myfunction.c:
#include <stdio.h>
void myfunc() { printf("hello world"); }
output after make:
gcc -Wall -g -O0 -c -o main.o main.c
gcc -Wall -g -O0 -c -o myfunction.o myfunction.c
gcc -Wall -g -O0 -o main main.o myfunction.o -lm
Undefined symbols for architecture x86_64:
"_myfunc", referenced from:
_main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [main] Error 1
I had something nearly identical working in the past. I have since clean installed MacOS and updated to Big Sur. Is this the issue or have I overlooked something?

Answer 1

I fixed the issue. I’m not sure what part fixed it, but installed Homebrew and used it to install gcc-10. I also deleted the project and started over.

Answer 2

myfunc would define like file header
myfunc.h
void myfunc()
Declare in another file
myfunc.c
void myfunc() { printf("hello world"); }
Follow the following tutorial
https://developer.gnome.org/anjuta-build-tutorial/stable/build-make.html.en