bench: add const qualifiers

Signed-off-by: Athan <[email protected]>

Author: kgryte

lib/node_modules/@stdlib/ndarray/base/ind2sub/benchmark/c/benchmark.c

@@ -99,11 +99,11 @@ static double benchmark1( void ) {
 	double t;
 	int i;
 
-	int64_t ndims = 3;
+	const int64_t ndims = 3;
 	const int64_t shape[] = { 10, 10, 10 };
 	const int64_t strides[] = { 100, -10, 1 };
-	int64_t offset = 90;
-	int64_t len = 1000;
+	const int64_t offset = 90;
+	const int64_t len = 1000;
 
 	int64_t out[ 3 ];