Brightness (NetBSD): add support for builtin display

src/detection/brightness/brightness_nbsd.c

@@ -0,0 +1,20 @@
+#include "brightness.h"
+
+#include "common/sysctl.h"
+
+const char* ffDetectBrightness(FF_MAYBE_UNUSED FFBrightnessOptions* options, FFlist* result)
+{
+    // https://man.netbsd.org/NetBSD-10.1/acpiout.4#DESCRIPTION
+
+    int value = ffSysctlGetInt("hw.acpi.acpiout0.brightness", -1);
+    if (value == -1)
+        return "sysctl(hw.acpi.acpiout0.brightness) failed";
+
+    FFBrightnessResult* brightness = (FFBrightnessResult*) ffListAdd(result);
+    ffStrbufInitStatic(&brightness->name, "acpiout");
+
+    brightness->max = 100;
+    brightness->min = 0;
+    brightness->current = value;
+    return NULL;
+}