[babl] meson: fix build for arch:i686 , cc:gcc-7

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 80347ef5b8706ddc0a2854dd5ff545b2d66ede4a
Author: Øyvind Kolås <pippin gimp org>
Date:   Sat May 25 18:35:57 2019 +0200

    meson: fix build for arch:i686 , cc:gcc-7
    
    Fixing issue #29 and merge reuqest !6.

 meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/meson.build b/meson.build
index e5ea943..9a827c0 100644
--- a/meson.build
+++ b/meson.build
@@ -207,6 +207,7 @@ if cc.has_argument('-mmmx') and get_option('enable-mmx')
             sse2_cflags = '-msse2'
             conf.set('USE_SSE2', 1, description:
               'Define to 1 if sse2 assembly is available.')
+            add_project_arguments('-march=native', language : 'c')
 
             # sse4.1 assembly
             if cc.has_argument('-msse4.1') and get_option('enable-sse4_1')