Can't solve linker error for small C program on CentOS 8.1

Question

I'm getting a linker error when I try to build a small C program on CentOS 8.1. I'm new to Linux development, and to using make, and I haven't been able to solve the error. The linker is failing to resolve a function that's defined in a static library. I built the static library from the sample code for the APUE book.

I'm able to build my program, if I use a makefile that's provided with the APUE sample code. But I'm trying to get it to build with a simpler makefile that I wrote.

The program is:

#include "apue.h"

int
main(void)
{
    err_exit(8, "hello world");
    exit(0);
}

The relevant line from the header file is:

void    err_exit(int, const char *, ...) __attribute__((noreturn));

The makefile is:

runme: testprog.o
    gcc -ansi -Wall -o runme -L. -lapue testprog.o

testprog.o: testprog.c
    gcc -c -ansi -Wall -o testprog.o -I. -DLINUX -D_GNU_SOURCE testprog.c

The error is:

$ make gcc -ansi -Wall -o runme -L. -lapue testprog.o testprog.o: In function main': testprog.c:(.text+0x14): undefined reference toerr_exit' collect2: error: ld returned 1 exit status make: *** [Makefile:2: runme] Error 1

Any suggestions would be appreciated.