Support for variable length arrays

[Stewori]

str1 = whatever;
if (strlen(str1) == 0) return whatever;
char str2[strlen(str1)+ 1];
strcpy(str2, str1);
whatever

becomes something like

str1 = whatever;
if (strlen(str1) == 0) return whatever;
{ char str2[strlen(str1)+ 1];
strcpy(str2, str1);
whatever
}

It could be done near-properly by using alloca, i.e. _alloca (for MSVC):

str1 = whatever;
if (strlen(str1) == 0) return whatever;
{ char* str2 = _alloca(strlen(str1) + 1);
strcpy(str2, str1);
whatever
}

In case it was a concious decision not to Support VLA, then this should be mentioned in the readme.
In general it would be helpful if known limits of c99-to-c89 were documented, at least roughly.

That said, it is still a more than helpful tool. Thanks for creating it!

[rbultje]

I don't think it was conscious, we implemented what we needed to get ffmpeg to compile and then it was "good enough" for us. I think we'd be happy to merge patches to support other (non-ffmpeg) features, but realistically a lot of people have moved on now that recent versions of MSVC semi-properly support C99...