I'm not sure if the gcc compiler has that option. The ld(GNU linker) can change the entry point label but its default is _start and it won't apply to your code.
Use entry as the explicit symbol for beginning execution of your
program, rather than the default entry point. If there is no
symbol named entry, the linker will try to parse entry as a
number, and use that as the entry address (the number will be
interpreted in base 10; you may use a leading 0x for base 16, or
a leading 0 for base 8).