configure: fix detection of VA/JPEG decoding API.

Fix detection of VA/JPEG decoding API with non-standard libva packages.
More precisely, some packages were shipping with a <va/va.h> header that
did not include <va/va_dec_jpeg.h>.

https://bugzilla.gnome.org/show_bug.cgi?id=706055

Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>

configure.ac

@@ -593,6 +593,12 @@ if test $USE_GLX -eq 1; then
 fi
 AC_SUBST(LIBVA_GLX_PKGNAME)
 
+dnl Check for va_dec_jpeg.h header
+saved_CPPFLAGS="$CPPFLAGS"
+CPPFLAGS="$CPPFLAGS $LIBVA_CFLAGS"
+AC_CHECK_HEADERS([va/va_dec_jpeg.h], [], [], [#include <va/va.h>])
+CPPFLAGS="$saved_CPPFLAGS"
+
 dnl Check for JPEG decoding API (0.32.1+)
 USE_JPEG_DECODER=0
 AC_CACHE_CHECK([for JPEG decoding API],
@@ -603,7 +609,11 @@ AC_CACHE_CHECK([for JPEG decoding API],
     LIBS="$LIBS $LIBVA_LIBS"
     AC_COMPILE_IFELSE(
         [AC_LANG_PROGRAM(
-            [[#include <va/va.h>]],
+            [[#include <va/va.h>
+              #ifdef HAVE_VA_VA_DEC_JPEG_H
+              #include <va/va_dec_jpeg.h>
+              #endif
+            ]],
             [[VAPictureParameterBufferJPEGBaseline pic_param;
               VASliceParameterBufferJPEGBaseline slice_param;
               VAHuffmanTableBufferJPEGBaseline huffman_table;

gst-libs/gst/vaapi/gstvaapidecoder_jpeg.c

@@ -34,6 +34,10 @@
 #include "gstvaapidisplay_priv.h"
 #include "gstvaapiobject_priv.h"
 
+#ifdef HAVE_VA_VA_DEC_JPEG_H
+# include <va/va_dec_jpeg.h>
+#endif
+
 #define DEBUG 1
 #include "gstvaapidebug.h"