here is mine:

V srtV(V*r,U n,U w){G*g;CO U b=1<<8*SZ(*g);U c[w][b+1];MS(c,0,SZ c);g=r;F(n,Fj(w,c[j][1+*g++]++))
 V*t=malloc(n*w);Q(t);F(w,U*ci=c[i];sumsU(ci+1,b-1);g=r;g+=i;Fj(n,MC(t+ci[g[w*j]]++*w,r+j*w,w))SWP(r,t))free(t);}

i'll add comment later

dzaima: Kamila

//universal sorter - sorts items of any given size
//r:array sorted in place
//n:length - number of items
//w:width - size of an item in bytes, must be even
V srtV(V*r,U n,U w){
 G*g;                      //same as r but reinterpreted as bytes (G means unsigned char)
 CO U b=1<<8*SZ(*g);       //256
 U c[w][b+1];              //counters
 MS(c,0,SZ c);             //memset with 0s
 g=r;
 F(n,Fj(w,c[j][1+*g++]++)) //go through g only once and do the counting for all of the w passes
 V*t=malloc(n*w);          //temporary helper array, will be swapped with r an even number of times
 Q(t);                     //assert(t!=NULL); - unnecessary
 F(w,                      //do w iterations, on the ith iteration sort by ith-least-significant byte
  U*ci=c[i];               //counters for the current iteration
  sumsU(ci+1,b-1);         //like +\ in k,  i should optimize it one day..
  g=r;g+=i;                //now I can change this to g=r+i; previously r had a different type from g
  Fj(n,
   MC(t+ci[g[w*j]]++*w,    //memcpy an item to the temp array; the compiler should replace it with
      r+j*w,               // a simple store instruction when srtV() is inlined and w is constant
      w);
  )
  SWP(r,t);                //swap
 )
 free(t);
}
//one day i'll also add a parameter for "key size", so i can sort by part of the item
//i'm still not sure if that or "grading" is more sensible

//"instantiate" srtV() for types U (32bit) and W (64bit); i'll add more when i need them
#define M(T) V srt##T(T*r,U n){srtV(r,n,SZ(T));}
 M(U)M(W)
#undef M

new improved version:

inline V srtV(V*r,U n,U w){U c[w][257];MS(c,0,SZ c);G*g=r;F(n,Fj(w,c[j][1+*g++]++))V*t=malloc(n*w);
 F(w,U*ci=c[i];sumsU(ci,256);g=r+i;Fj(n,MC(t+ci[g[w*j]]++*w,r+j*w,w))SWP(r,t))I(w&1,SWP(r,t);MC(r,t,n*w))free(t);}