chore: fix C lint errors (issue #6887)

Signed-off-by: Lalit Narayan Yadav <[email protected]>

Author: LalitNarayanYadav

lib/node_modules/@stdlib/stats/base/dmeanvarpn/benchmark/c/benchmark.length.c

@@ -97,10 +97,16 @@ static double rand_double( void ) {
 static double benchmark( int iterations, int len ) {
 	double elapsed;
 	double out[ 2 ];
-	double x[ len ];
+	double *x;
 	double t;
 	int i;
 
+	x = malloc(len * sizeof(double));
+	if (x == NULL) {
+		fprintf(stderr, "Memory allocation failed\n");
+		exit(1);
+	}
+
 	for ( i = 0; i < len; i++ ) {
 		x[ i ] = ( rand_double() * 20000.0 ) - 10000.0;
 	}