[babl] meson: fix AVX2 detection on x86

[Ell <ell src gnome org>]

commit 2fa0be1b3ba3f0256d12c6b37e2bb39baf237364
Author: Ell <ell_se yahoo com>
Date:   Tue Jul 30 20:37:18 2019 +0300

    meson: fix AVX2 detection on x86
    
    s/rax/eax/

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 3a22e1b..9389b3f 100644
--- a/meson.build
+++ b/meson.build
@@ -219,7 +219,7 @@ if cc.has_argument('-mmmx') and get_option('enable-mmx')
 
               # avx2 assembly
               if cc.has_argument('-mavx2') and get_option('enable-avx2')
-                if cc.compiles('asm ("vpgatherdd %ymm0,(%rax,%ymm1,4),%ymm2");')
+                if cc.compiles('asm ("vpgatherdd %ymm0,(%eax,%ymm1,4),%ymm2");')
                   message('avx2 assembly available')
                   avx2_cflags = '-mavx2'
                   conf.set('USE_AVX2', 1, description: