I suspect that C11 support is closer than C99 support (and it would be good too). Things like variable length arrays are now optional.
C11 adds some non-optional features whch needs compiler support (alignment specifiers, type-generic selections, unicode literals, ...).
Do you really think vendors which don' care about C99 will suddenly jump to implement all mandatory C11 features?
Look at the C99 rationale:
The inability to declare arrays whose size is known only at execution time was often cited as a primary deterrent to using C as a numerical computing language.
That's also the main reason for the introduction of complex types and type-generic math functions.
It's not as if the C committee got together and thought "Hey, what can we do to piss off compiler writers?" - there was actual demand for these features!
Sure, it made language semantics messier (runtime evaluation of sizeof, introduction of variably-modified types restricted to block or prototype scope, magical macros for math functions - which has been fixed with C11, btw), but C99 is indeed a superior language than C90 for doing numerics.
In fact, we've de-facto had such a mechanism for decades, but it hasn't been codified anywhere, actually for some of the same reasons people don't appreciate VLAs, but it at least rests much more comfortably with the rest of the language.
At some point, you go from enhancing C to breaking it in the interests of a small minority (who apparently don't want to use Fortran?). VLAs are, if not over the line, right on it.
In fact, we've de-facto had such a mechanism for decades
Unfortunately, that's not the case. There are actually two primary use cases for VLAs:
1. Variable-length multi-dimensional array parameters:
// C99
double trace(size_t n, double mat[][n])
{
double sum = 0;
for(size_t i = 0; i < n; ++i)
sum += mat[i][i];
return sum;
}
/* C90 */
double trace(size_t n, double mat[])
{
double sum = 0;
size_t i = 0;
for(; i < n; ++i)
sum += mat[i * n + i];
return sum;
}
2. Allocation of variably-sized objects with automatic storage duration. Some libc implementations provide alloca() for that purpose -- unfortunately, it has issues (see eg http://c-faq.com/malloc/alloca.glb.html ).