bench: refactor to use dynamic memory allocation in strided/base/dmap

PR-URL: #11566
Ref: #8643

Reviewed-by: Philipp Burckhardt <pburckhardt@outlook.com>

Author: anandkaranubc

lib/node_modules/@stdlib/strided/base/dmap/benchmark/c/benchmark.length.c

@@ -106,11 +106,13 @@ static double identity( const double x ) {
 */
 static double benchmark( int iterations, int len ) {
 	double elapsed;
-	double x[ len ];
-	double y[ len ];
+	double *x;
+	double *y;
 	double t;
 	int i;
 
+	x = (double *)malloc( len * sizeof( double ) );
+	y = (double *)malloc( len * sizeof( double ) );
 	for ( i = 0; i < len; i++ ) {
 		x[ i ] = ( rand_double()*200.0 ) - 100.0;
 		y[ i ] = 0.0;
@@ -128,6 +130,8 @@ static double benchmark( int iterations, int len ) {
 	if ( y[ i%len ] != y[ i%len ] ) {
 		printf( "should not return NaN\n" );
 	}
+	free( x );
+	free( y );
 	return elapsed;
 }