Main Function required

[nahumj]

Even if a test case has "run_main=false", the test cases will fail to compile unless a main function is provided in the solution.

Example compiler error:

/usr/lib/gcc/x86_64-linux-gnu/11/../../../x86_64-linux-gnu/Scrt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status

[mercere99]

I'll have to think a bit for how this should be handled. I'm not sure how to detect main(). If main is explicitly not written by the students, we can always put it in the header.