build: stop defining unused VERSION

Scons and autotools don't define it, and as of last commit nothing
uses it.

`VERSION` is also a generic enough name that something somewhere will
eventually clash, and we don't want to repeat the LLVM `DEBUG` fiasco.

Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
diff --git a/meson.build b/meson.build
index 33f4e5a..df9043e 100644
--- a/meson.build
+++ b/meson.build
@@ -43,8 +43,7 @@
   '-D__STDC_CONSTANT_MACROS',
   '-D__STDC_FORMAT_MACROS',
   '-D__STDC_LIMIT_MACROS',
-  '-DVERSION="@0@"'.format(meson.project_version()),
-  '-DPACKAGE_VERSION=VERSION',
+  '-DPACKAGE_VERSION="@0@"'.format(meson.project_version()),
   '-DPACKAGE_BUGREPORT="https://bugs.freedesktop.org/enter_bug.cgi?product=Mesa"',
 ]