[Partial RFC] modesetting: support dri3 through glamor

This was really trivial, took me about an hour. I had some issues running Vulkan due to DRI3 issues(without MESA and using modesetting), that may have been because my distrubution didnt compile it for some reason though. This is only compile tested right now(on server 1.20), because I think there is something I missed here(as in DRI3 is supported in modesetting somewhere else I dont know about), hence the [Partial RFC].

include/os.h

@@ -322,6 +322,9 @@ xstrcasestr(const char *s, const char *find);
 #ifndef HAVE_STRLCPY
 extern _X_EXPORT size_t
 strlcpy(char *dst, const char *src, size_t siz);
+#endif
+
+#ifndef HAVE_STRLCAT
 extern _X_EXPORT size_t
 strlcat(char *dst, const char *src, size_t siz);
 #endif

[Enrico Weigelt, metux IT consult .]

Do we even still need our string functions at all ?

@alanc @whot

[Alan Coopersmith]

strlcat & strlcpy? I suppose we could drop support for GNU libc versions older than 2.38, but that would probably eliminate most of the enterprise linux distros that are the ones left still packaging Xorg. Since glibc 2.38 just released a year ago, that seems a bit aggressive.