如何在 Clion 中编译几个“.c”文件？

Question

我有一个包含多个“.c”文件的项目，当我使用 CLion 编译它时，出现以下错误：

"D:\JetBrains\CLion 2020.3.2\bin\cmake\win\bin\cmake.exe" --build D:\CLionProjects\gobackn\cmake-
build-debug --target all -- -j 9
[ 50%] Linking C executable gobackn.exe
CMakeFiles\gobackn.dir/objects.a(main.c.obj): In function `put_frame':
D:/CLionProjects/gobackn/main.c:42: undefined reference to `crc32'
D:/CLionProjects/gobackn/main.c:43: undefined reference to `send_frame'
CMakeFiles\gobackn.dir/objects.a(main.c.obj): In function `send_data':
D:/CLionProjects/gobackn/main.c:56: undefined reference to `stop_ack_timer'
D:/CLionProjects/gobackn/main.c:61: undefined reference to `dbg_frame'
D:/CLionProjects/gobackn/main.c:63: undefined reference to `start_timer'
D:/CLionProjects/gobackn/main.c:65: undefined reference to `dbg_frame'
D:/CLionProjects/gobackn/main.c:68: undefined reference to `dbg_frame'
CMakeFiles\gobackn.dir/objects.a(main.c.obj): In function `main':
D:/CLionProjects/gobackn/main.c:87: undefined reference to `protocol_init'
D:/CLionProjects/gobackn/main.c:88: undefined reference to `lprintf'
D:/CLionProjects/gobackn/main.c:89: undefined reference to `lprintf'
D:/CLionProjects/gobackn/main.c:91: undefined reference to `disable_network_layer'
D:/CLionProjects/gobackn/main.c:98: undefined reference to `wait_for_event'
D:/CLionProjects/gobackn/main.c:102: undefined reference to `get_packet'
D:/CLionProjects/gobackn/main.c:113: undefined reference to `recv_frame'
D:/CLionProjects/gobackn/main.c:115: undefined reference to `crc32'
D:/CLionProjects/gobackn/main.c:116: undefined reference to `dbg_event'
D:/CLionProjects/gobackn/main.c:123: undefined reference to `dbg_frame'
D:/CLionProjects/gobackn/main.c:125: undefined reference to `dbg_frame'
D:/CLionProjects/gobackn/main.c:126: undefined reference to `put_packet'
D:/CLionProjects/gobackn/main.c:129: undefined reference to `start_ack_timer'
D:/CLionProjects/gobackn/main.c:131: undefined reference to `dbg_frame'
D:/CLionProjects/gobackn/main.c:138: undefined reference to `dbg_frame'
D:/CLionProjects/gobackn/main.c:147: undefined reference to `dbg_frame'
D:/CLionProjects/gobackn/main.c:151: undefined reference to `stop_timer'
D:/CLionProjects/gobackn/main.c:157: undefined reference to `dbg_event'
D:/CLionProjects/gobackn/main.c:171: undefined reference to `enable_network_layer'
D:/CLionProjects/gobackn/main.c:173: undefined reference to `disable_network_layer'
collect2.exe: error: ld returned 1 exit status
mingw32-make.exe[2]: *** [gobackn.exe] Error 1
mingw32-make.exe[1]: *** [CMakeFiles/gobackn.dir/all] Error 2
mingw32-make.exe: *** [all] Error 2
CMakeFiles\gobackn.dir\build.make:104: recipe for target 'gobackn.exe' failed
CMakeFiles\Makefile2:94: recipe for target 'CMakeFiles/gobackn.dir/all' failed
Makefile:102: recipe for target 'all' failed

我的项目结构如图：

有人想告诉我在这个过程中发生了什么以及如何解决它吗？