Add compatibility define for pci_device_is_boot_display()

It will take some time for a new libpciaccess to be released and
even then bumping the dependency for libpciaccess isn't attractive.
If an older libpciaccess is used just add a static inline define.

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2038>

hw/xfree86/common/xf86_pci_priv.h

@@ -18,7 +18,7 @@ struct pci_device;
  * callee code is already prepared for using it, but for the time being
  * we need a dummy - until the actual one is really there.
  */
-#ifndef pci_device_is_boot_display
+#ifndef HAVE_PCI_DEVICE_IS_BOOT_DISPLAY
 static inline int pci_device_is_boot_display(struct pci_device *dev)
 {
     return 0;

include/meson.build

@@ -327,6 +327,11 @@ conf_data.set('PCVT_SUPPORT', supports_pcvt ? '1' : false)
 conf_data.set('SYSCONS_SUPPORT', supports_syscons ? '1' : false)
 conf_data.set('WSCONS_SUPPORT', supports_wscons ? '1' : false)
 conf_data.set('XSERVER_LIBPCIACCESS', get_option('pciaccess') ? '1' : false)
+if get_option('pciaccess')
+    pciaccess_dep = dependency('pciaccess', required: build_xorg)
+    conf_data.set('HAVE_PCI_DEVICE_IS_BOOT_DISPLAY',
+                  cc.has_function('pci_device_is_boot_display', dependencies: pciaccess_dep) ? '1' : false)
+endif
 conf_data.set('XSERVER_PLATFORM_BUS', build_udev_kms ? '1' : false)
 conf_data.set('XSERVER_SCREEN_VRR', '1')