diff --git a/matrix.go b/matrix.go
index 82961fc..ea9f635 100644
--- a/matrix.go
+++ b/matrix.go
@@ -58,11 +58,6 @@ var DefaultConfig = HardwareConfig{
 	ScanMode:          Progressive,
 }
 
-type RuntimeOptions struct {
-	// Control speed of GPIO updates. Valid range is 0..3
-	GPIOSlowdown int
-}
-
 // HardwareConfig rgb-led-matrix configuration
 type HardwareConfig struct {
 	// Rows the number of rows supported by the display, so 32 or 16.
@@ -175,6 +170,8 @@ const MatrixEmulatorENV = "MATRIX_EMULATOR"
 func stringsToC(s []string) **C.char {
 	cArray := C.malloc(C.size_t(len(s)) * C.size_t(unsafe.Sizeof(uintptr(0))))
 
+	a := (*[len(s) - 1]*C.char)(cArray)
+
 	for idx, substring := range s {
 		a[idx] = C.CString(substring)
 	}