Those cast issues should have been fixed in MESS SVN last night. I do still get some different warnings in MSVC though:

Quote
src\mame\video\n64.c(3488) : warning C4819: The file contains a character that cannot be represented in the current code page (932). Save the file in Unicode format to prevent data loss
c:\games\emulated\mess\src\mame\video\n64.c(4271) : warning C4701: potentially uninitialized local variable 'dsdeh' used
c:\games\emulated\mess\src\mame\video\n64.c(4272) : warning C4701: potentially uninitialized local variable 'dtdeh' used
c:\games\emulated\mess\src\mame\video\n64.c(4273) : warning C4701: potentially uninitialized local variable 'dwdeh' used
c:\games\emulated\mess\src\mame\video\n64.c(4274) : warning C4701: potentially uninitialized local variable 'drdeh' used
c:\games\emulated\mess\src\mame\video\n64.c(4275) : warning C4701: potentially uninitialized local variable 'dgdeh' used
c:\games\emulated\mess\src\mame\video\n64.c(4276) : warning C4701: potentially uninitialized local variable 'dbdeh' used
c:\games\emulated\mess\src\mame\video\n64.c(4277) : warning C4701: potentially uninitialized local variable 'dadeh' used
c:\games\emulated\mess\src\mame\video\n64.c(4278) : warning C4701: potentially uninitialized local variable 'dzdeh' used
c:\games\emulated\mess\src\mame\video\n64.c(1859) : warning C4701: potentially uninitialized local variable 't0' used
c:\games\emulated\mess\src\mame\video\n64.c(1864) : warning C4701: potentially uninitialized local variable 't3' used

(The Unicode thing is because of a comment in what appears to be the legacy Windows Russian encoding on line 4008. I'd convert it myself if it wasn't in a src/mame/ file.)