Undefined reference - built from source DMD

[Stefanos Baziotis]

I don't if this the right group to post this.

DMD built from source fails to link / find `main`. The error is:
/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/Scrt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status
Error: linker exited with status 1

Does anyone know how this could have happened?