bench: refactor to use dynamic memory allocation in blas/ext/base/slinspace

PR-URL: stdlib-js#10768
Ref: stdlib-js#8643

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

Author: prajjwalbajpai

lib/node_modules/@stdlib/blas/ext/base/slinspace/benchmark/c/benchmark.length.c

@@ -97,10 +97,11 @@ static float rand_float( void ) {
 */
 static double benchmark1( int iterations, int len ) {
 	double elapsed;
-	float x[ len ];
+	float *x;
 	double t;
 	int i;
 
+	x = (float *) malloc( len * sizeof( float ) );
 	for ( i = 0; i < len; i++ ) {
 		x[ i ] = ( rand_float()*200.0f ) - 100.0f;
 	}
@@ -116,6 +117,7 @@ static double benchmark1( int iterations, int len ) {
 	if ( x[ 0 ] != x[ 0 ] ) {
 		printf( "should not return NaN\n" );
 	}
+	free( x );
 	return elapsed;
 }
 
@@ -128,10 +130,11 @@ static double benchmark1( int iterations, int len ) {
 */
 static double benchmark2( int iterations, int len ) {
 	double elapsed;
-	float x[ len ];
+	float *x;
 	double t;
 	int i;
 
+	x = (float *) malloc( len * sizeof( float ) );
 	for ( i = 0; i < len; i++ ) {
 		x[ i ] = ( rand_float()*200.0f ) - 100.0f;
 	}
@@ -147,6 +150,7 @@ static double benchmark2( int iterations, int len ) {
 	if ( x[ 0 ] != x[ 0 ] ) {
 		printf( "should not return NaN\n" );
 	}
+	free( x );
 	return elapsed;
 }