[babl] build: issue #41 builds without mmx/sse etc extensions do not work

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

commit 030303d8c1528232efba1f6ac9425352903764df
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Aug 2 13:53:44 2019 +0200

    build: issue #41 builds without mmx/sse etc extensions do not work
    
    The warnings about the SIMD flags specific variables not being set goes
    away with this commit. Setting empty strings do not work since then gcc
    ends up looking for input files that are the empty string, thus this patch
    re-adds -Wall instead of setting an empty string.

 meson.build | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
---
diff --git a/meson.build b/meson.build
index 66aa981..85a8554 100644
--- a/meson.build
+++ b/meson.build
@@ -215,6 +215,8 @@ if cc.has_argument('-mmmx') and get_option('enable-mmx')
                 sse4_1_cflags = '-msse4.1'
                 conf.set('USE_SSE4_1', 1, description:
                   'Define to 1 if sse4.1 assembly is available.')
+              else
+                sse4_1_cflags = '-Wall'
               endif
 
               # avx2 assembly
@@ -224,11 +226,21 @@ if cc.has_argument('-mmmx') and get_option('enable-mmx')
                   avx2_cflags = '-mavx2'
                   conf.set('USE_AVX2', 1, description:
                     'Define to 1 if avx2 assembly is available.')
+                else
+                  avx2_cflags = '-Wall'
                 endif
+              else
+                avx2_cflags = '-Wall'
               endif
             endif
+          else
+            sse2_cflags = '-Wall'
           endif
+        else
+          sse2_args = ['-Wall']
         endif
+      else
+        sse_args = ['-Wall']
       endif
       if cc.has_argument('-mf16c') and get_option('enable-f16c')
         if cc.compiles(
@@ -242,8 +254,14 @@ if cc.has_argument('-mmmx') and get_option('enable-mmx')
             'Define to 1 if f16c intrinsics are available.')
         endif
       endif
+    else
+      sse_args = '-Wall'
     endif
+  else
+    mmx_args = '-Wall'
   endif
+else
+  mmx_args = '-Wall'
 endif
 
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