Warnings from C code

[fredrikz]

It would be nice if volk could fix some warnings emitted from the volk.h/volk.c when enabling really high warning levels, both on Windows and Linux. The offending code is declarations and definitions which uses the form:

VkResult foo();
VkResult foo() {
...
}

instead of

VkResult foo(void);
VkResult foo(void) {
...
}

On VS2017 the warning emitted is C4255 (https://msdn.microsoft.com/en-us/library/0k9z2ey4.aspx) and on Linux -Wstrict-prototypes (which complains about the missing void) and -Wmissing-prototypes (which follows since the prototypes aren't defined). All in all, not a big issue, but also a simple fix?

[zeux]

Thanks! I wasn't aware of this distinction previously.