diff --git a/meson.build b/meson.build
index 0760a30d6f6..be02b413120 100644
--- a/meson.build
+++ b/meson.build
@@ -1990,9 +1990,6 @@ if with_osmesa
       error('OSMesa bits must be 8 if building glx or dri based drivers')
     endif
     osmesa_lib_name = osmesa_lib_name + osmesa_bits
-    pre_args += [
-      '-DCHAN_BITS=@0@'.format(osmesa_bits), '-DDEFAULT_SOFTWARE_DEPTH_BITS=31'
-    ]
   endif
 endif