xfree86: compat: re-add xf86Msg() for badly maintained drivers.

NVidia yet again lagging behind a year with trivial cleanups,
even though they're informed about this function being deprecated
and dropped.

It spills out a log warning calling users to file bug reports their
driver vendor.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

hw/xfree86/compat/README

@@ -0,0 +1 @@
+special compat code for legacy drivers, namely Nvidia proprietary

hw/xfree86/compat/log.c

@@ -0,0 +1,28 @@
+#include <dix-config.h>
+
+#include <X11/Xfuncproto.h>
+
+#include "include/os.h"
+
+#undef xf86Msg
+
+/*
+ * this is specifically for NVidia proprietary driver: they're again lagging
+ * behind a year, doing at least some minimal cleanup of their code base.
+ * All attempts to get in direct contact with them have failed.
+ */
+_X_EXPORT void xf86Msg(MessageType type, const char *format, ...)
+    _X_ATTRIBUTE_PRINTF(2, 3);
+
+void xf86Msg(MessageType type, const char *format, ...)
+{
+    LogMessageVerb(X_WARNING, 0, "Outdated driver still using xf86Msg() !\n");
+    LogMessageVerb(X_WARNING, 0, "File a bug report to driver vendor or use a FOSS driver.\n");
+    LogMessageVerb(X_WARNING, 0, "Proprietary drivers are inherently unstable, they just can't be done right.\n");
+
+    va_list ap;
+
+    va_start(ap, format);
+    LogVMessageVerb(type, 1, format, ap);
+    va_end(ap);
+}

hw/xfree86/compat/meson.build

@@ -0,0 +1,8 @@
+srcs_xorg_compat = [
+    'log.c',
+]
+
+xorg_compat = static_library('xorg_compat',
+    srcs_xorg_compat,
+    include_directories: [inc, xorg_inc, top_dir_inc],
+)

hw/xfree86/meson.build

@@ -24,6 +24,7 @@ endif
 
 # subdirs for convenience libraries statically linked into Xorg
 subdir('common')
+subdir('compat')
 subdir('ddc')
 if build_dri1
     subdir('dri')
@@ -53,6 +54,7 @@ xorg_link = [
     libxserver,
     libglxvnd,
     xorg_common,
+    xorg_compat,
     xorg_loader,
     xorg_ddc,
     xorg_xkb,