meson: use include_directories() with external OMX headers path

It seems cleaner to use the proper meson tools to include this path
rather than manually tweak the build flags.

This also allows us to simplify the OMX extensions detection code. We
are now always checking which files are present, even when using our
internal copy of OMX, rather than hardcoding the ones present in it.

https://bugzilla.gnome.org/show_bug.cgi?id=792043

meson.build

@@ -169,7 +169,9 @@ gst_omx_args = ['-DHAVE_CONFIG_H']
 configinc = include_directories('.')
 omx_header_path = get_option('with_omx_header_path')
 if omx_header_path != ''
-  gst_omx_args += ['-I' + omx_header_path]
+  omx_inc = include_directories (omx_header_path)
+else
+  omx_inc = include_directories (join_paths ('omx', 'openmax'))
 endif
 
 default_omx_struct_packing = 0
@@ -204,6 +206,7 @@ elif omx_target == 'zynqultrascaleplus'
   have_allegro_header = cc.has_header (
       'OMX_Allegro.h',
       args : gst_omx_args,
+      include_directories : [omx_inc],
       required : false)
   if not have_allegro_header
     error ('Need Allegro OMX headers to build for Zynq UltraScale+. Use with_omx_header_path option to specify the path of those headers.')
@@ -218,46 +221,32 @@ else
   error ('Unsupported omx target specified. Use the -Dwith_omx_target option')
 endif
 
-have_external_omx = cc.has_header(
-    'OMX_Core.h',
-    args : gst_omx_args,
-    required : false)
 extra_video_headers = ''
-# Our internal OpenMAX IL headers have OMX_VideoExt.h, OMX_IndexExt.h and OMX_ComponentExt.h
-have_video_ext = true
-have_index_ext = true
-have_component_ext = true
+# Check for optional OpenMAX extension headers
 
-if have_external_omx
-  have_video_ext = cc.has_header (
-      'OMX_VideoExt.h',
-      args : gst_omx_args,
-      required : false)
-  if have_video_ext
-    extra_video_headers += '''
+if cc.has_header (
+    'OMX_VideoExt.h',
+    args : gst_omx_args,
+    include_directories : [omx_inc],
+    required : false)
+  extra_video_headers += '''
 #include <OMX_VideoExt.h>'''
-  endif
-
-  have_index_ext = cc.has_header (
-      'OMX_IndexExt.h',
-      args : gst_omx_args,
-      required : false)
-
-  have_component_ext = cc.has_header (
-      'OMX_ComponentExt.h',
-      args : gst_omx_args,
-      required : false)
-endif
-
-if have_video_ext
   cdata.set ('HAVE_VIDEO_EXT', 1)
 endif
 
-if have_index_ext
+if cc.has_header (
+    'OMX_IndexExt.h',
+    args : gst_omx_args,
+    include_directories : [omx_inc],
+    required : false)
   cdata.set ('HAVE_INDEX_EXT', 1)
 endif
 
-if have_component_ext
+if cc.has_header (
+    'OMX_ComponentExt.h',
+    args : gst_omx_args,
+    include_directories : [omx_inc],
+    required : false)
   cdata.set ('HAVE_COMPONENT_EXT', 1)
 endif
 
@@ -266,6 +255,7 @@ have_omx_vp8 = cc.has_header_symbol(
     'OMX_VIDEO_CodingVP8',
     prefix : extra_video_headers, 
     args : gst_omx_args,
+    include_directories : [omx_inc],
     required : false)
 if have_omx_vp8
   cdata.set('HAVE_VP8', 1)
@@ -276,6 +266,7 @@ have_omx_theora = cc.has_header_symbol(
     'OMX_VIDEO_CodingTheora',
     prefix : extra_video_headers,
     args : gst_omx_args,
+    include_directories : [omx_inc],
     required : false)
 if have_omx_theora
   cdata.set('HAVE_THEORA', 1)
@@ -286,6 +277,7 @@ have_omx_hevc = cc.has_header_symbol(
     'OMX_VIDEO_CodingHEVC',
     prefix : extra_video_headers,
     args : gst_omx_args,
+    include_directories : [omx_inc],
     required : false)
 if have_omx_hevc
   cdata.set('HAVE_HEVC', 1)

omx/meson.build

@@ -26,7 +26,6 @@ omx_sources = [
   'gstomxmp3enc.c',
 ]
 
-extra_inc = []
 extra_c_args = []
 
 if have_omx_vp8
@@ -43,10 +42,6 @@ if have_omx_hevc
   omx_sources += 'gstomxh265dec.c'
 endif
 
-if not have_external_omx
-  extra_inc += include_directories ('openmax')
-endif
-
 optional_deps = []
 if gstgl_dep.found()
   optional_deps += gstgl_dep
@@ -57,7 +52,7 @@ gstomx = library('gstomx',
   omx_sources,
   c_args : gst_omx_args + extra_c_args,
 #  link_args : noseh_link_args,
-  include_directories : [configinc] + extra_inc,
+  include_directories : [configinc, omx_inc],
   dependencies : [gstvideo_dep, gstaudio_dep, gstbase_dep, gstcontroller_dep,
                   libm, gmodule_dep, gstallocators_dep] + optional_deps,
   install : true,

tools/meson.build

@@ -1,7 +1,7 @@
 executable('listcomponents',
   'listcomponents.c',
   install: false,
-  include_directories : [configinc] + extra_inc,
+  include_directories : [configinc, omx_inc],
   dependencies : [glib_dep, gmodule_dep],
   link_with: [],
   c_args : gst_omx_args + extra_c_args,