Fix Assembler Warning: mnemonic suffix used with `div'

[kimwalisch]

This merge request fixes the following assembler warning that occurs when compiling using the upcoming GCC 15 on MinGW-w64/MSYS (Windows 11) for x86-64 CPUs:

C:\msys64\tmp\ccEHfp1X.s: Assembler messages:
C:\msys64\tmp\ccEHfp1X.s:7548: Warning: mnemonic suffix used with `div'
C:\msys64\tmp\ccEHfp1X.s:7548: Warning: NOTE: Such forms are deprecated and will be rejected by a future version of the assembler

Note that the warning is only emitted for __x86_64__ but not for __i386__. Hence __asm__("divl ..." can remain as is for the time being.