Mesa (master): meson+dri3: allow building against older xcb (v3)

[Rob Clark]

Module: Mesa
Branch: master
Commit: bc5001325b876afbd9fbb7186174e085e0b06206
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=bc5001325b876afbd9fbb7186174e085e0b06206

Author: Rob Clark <robdclark at gmail.com>
Date:   Tue Mar 13 19:00:45 2018 -0400

meson+dri3: allow building against older xcb (v3)

Similar to previous patch, make xcb 1.13 optional.

Signed-off-by: Rob Clark <robdclark at gmail.com>
Reviewed-by: Dylan Baker <dylan at pnwbakers.com>

---

 meson.build | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/meson.build b/meson.build
index 557e9ef339..a59736f50a 100644
--- a/meson.build
+++ b/meson.build
@@ -1235,9 +1235,14 @@ if with_platform_x11
     dep_xcb_dri2 = dependency('xcb-dri2', version : '>= 1.8')
 
     if with_dri3
-      pre_args += '-DHAVE_DRI3 -DHAVE_DRI3_MODIFIERS'
-      dep_xcb_dri3 = dependency('xcb-dri3', version : '>= 1.13')
-      dep_xcb_present = dependency('xcb-present', version: '>= 1.13')
+      pre_args += '-DHAVE_DRI3'
+      dep_xcb_dri3 = dependency('xcb-dri3')
+      dep_xcb_present = dependency('xcb-present')
+      # until xcb-dri3 has been around long enough to make a hard-dependency:
+      if (dep_xcb_dri3.version().version_compare('>= 1.13') and
+          dep_xcb_present.version().version_compare('>= 1.13'))
+        pre_args += '-DHAVE_DRI3_MODIFIERS'
+      endif
       dep_xcb_sync = dependency('xcb-sync')
       dep_xshmfence = dependency('xshmfence', version : '>= 1.1')
     endif