bench: fix missing variable declarations

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

Author: kgryte

lib/node_modules/@stdlib/math/base/special/ccis/benchmark/c/native/benchmark.c

@@ -95,6 +95,8 @@ static double benchmark( void ) {
 	double are[ 100 ];
 	double aim[ 100 ];
 	double elapsed;
+	double re;
+	double im;
 	double t;
 	int i;