xfree86: modesettig: fix missing include of <errno.h>

It's much cleaner to always include directly what one needs,
instead of relying on very indirect including.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1435>

hw/xfree86/drivers/modesetting/dri2.c

@@ -36,7 +36,9 @@
 #include "dix-config.h"
 #endif
 
+#include <errno.h>
 #include <time.h>
+
 #include "list.h"
 #include "xf86.h"
 #include "driver.h"

hw/xfree86/drivers/modesetting/driver.c

@@ -36,8 +36,10 @@
 #include "dix-config.h"
 #endif
 
+#include <errno.h>
 #include <unistd.h>
 #include <fcntl.h>
+
 #include "xf86.h"
 #include "xf86Priv.h"
 #include "xf86_OSproc.h"

hw/xfree86/drivers/modesetting/pageflip.c

@@ -24,6 +24,8 @@
 #include "dix-config.h"
 #endif
 
+#include <errno.h>
+
 #include <xserver_poll.h>
 #include <xf86drm.h>
 

hw/xfree86/drivers/modesetting/vblank.c

@@ -29,7 +29,9 @@
 #include "dix-config.h"
 #endif
 
+#include <errno.h>
 #include <unistd.h>
+
 #include <xf86.h>
 #include <xf86Crtc.h>
 #include "driver.h"