C - Union of struct and array, ugly syntax

I'm writing some floating pointer vector types in C. Using a union, I can get both struct and array representations of the same type, depending on which is more convenient. The syntax is very ugly, though:

#include <stdio.h>
#include <tgmath.h>
typedef union {
    struct { float x, y; };
    float val[2];
} vec2;
int main(int argc, char *argv[]) {
    vec2 herp = {{3, 4}}; // using {3, 4} throws an error when -Wall is enabled
    printf("Vector: {%f, %f}\n", herp.x, herp.y);
    float len = sqrt(herp.x * herp.x + herp.y * herp.y);
    printf("Length: %f\n", len);
    vec2 normalized = {{herp.val[0] / len, herp.val[1] / len}};
    printf("Normalized: {%f, %f}\n", normalized.val[0], normalized.val[1]);
}

Is there any way, using C99, C11, or possibly even GNU C extensions, that I can get syntax like the following?

vec2 derp = {6, 20}; // no need for two sets of braces in initializers
derp[0] = 5; // "anonymous" array

or am I better off making my vectors only structs or only arrays, and casting them to the other type when the alternative syntax is more convenient? (.x and .y are more convenient most of the time, but treating them as arrays will be more convenient for operations between vectors and matrices)

I know this is trivial shit but I want to get it right before I go any further.

>>41
LARGER projects [...] will prefer vectors and strings over cstrings and arrays.
Big projects should use neither C nor C++ if not absolutely necessary. This proves nothing.

Move semantics
Only needed because of a stupid C heirloom that crippled C++ as a language from the get-go.

Type inference
Should have been added as soon as the STL was made. The fact that someone thought having to write vector<type>::iterator in every for-loop on things like vectors shows that this language is designed so badly it's not even funny.

Lambdas
Are flaky as hell, utilize awful syntax as lambdas have problems with the ALGOL style and require ridiculous attention to detail because they are brought into an inferior imperative language.

Constexprs
Because C++ obviously needs even more compiler optimization keywords. It's like Fortran all over again, only worse designed.