Fix a memory-management goof.

That's what I get for actually trying to free my memory :-)

makecab.c

@@ -8,7 +8,7 @@
 #include "uchars.h"
 
 typedef struct CabCreateContext {
-    char *outfile;
+    char *outfile;                     /* aliases one of args[] */
 
     char **args;
     int nargs, argsize;
@@ -67,7 +67,6 @@ void CreateCabCancel(CabCreateContext *ctx)
     for (int i = 0; i < ctx->nargs; i++)
         sfree(ctx->args[i]);
     sfree(ctx->args);
-    sfree(ctx->outfile);
     sfree(ctx);
 }