[gdk-pixbuf/ebassi/for-master: 3/3] build: Fix libjpeg checks

[Emmanuele Bassi <ebassi src gnome org>]

commit 9284c568592645661af87febf5efd1c6bb28d424
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Fri Apr 16 18:32:34 2021 +0100

    build: Fix libjpeg checks
    
    We are checking for libjpeg only if we find a header to include, but the
    dependency check with pkg-config, and the fallback with a wrap file,
    should happen outside of that check.

 meson.build | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)
---
diff --git a/meson.build b/meson.build
index 4724bf5cc..738e447d4 100644
--- a/meson.build
+++ b/meson.build
@@ -332,17 +332,30 @@ if get_option('jpeg') and not native_windows_loaders
       jpeg_dep = cc.find_library('libjpeg', required: false)
     endif
 
-    if not jpeg_dep.found()
-      jpeg_dep = dependency('libjpeg', required: false, fallback: 'libjpeg')
+    if jpeg_dep.found()
+      enabled_loaders += 'jpeg'
+      loaders_deps += jpeg_dep
     endif
+  endif
+
+  # If we couldn't find libjpeg in our include/linker paths,
+  # then use pkg-config, and if that fails, fall back to the
+  # wrap
+  if not enabled_loaders.contains('jpeg')
+    jpeg_dep = dependency('libjpeg', required: false, fallback: 'libjpeg')
 
-    if jpeg_dep.found() and cc.has_function('jpeg_destroy_decompress', dependencies: jpeg_dep)
+    if jpeg_dep.found()
       enabled_loaders += 'jpeg'
       loaders_deps += jpeg_dep
+    endif
+  endif
+
+  if jpeg_dep.found()
+    has_destroy_decompress = cc.has_function('jpeg_destroy_decompress', dependencies: jpeg_dep)
+    has_simple_progression = cc.has_function('jpeg_simple_progression', dependencies: jpeg_dep)
 
-      gdk_pixbuf_conf.set('HAVE_PROGRESSIVE_JPEG',
-                          cc.has_function('jpeg_simple_progression',
-                                          dependencies: jpeg_dep))
+    if has_destroy_decompress and has_simple_progression
+      gdk_pixbuf_conf.set('HAVE_PROGRESSIVE_JPEG', has_simple_progression)
     endif
   endif
 endif