[FFmpeg-cvslog] configure: add direct detection of libopencv

[Andreas Cadhalpun]

ffmpeg | branch: master | Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> | Sun Feb  7 23:25:53 2016 +0100| [15708f13477aaf2effdc0d7fc727507bc468335a] | committer: Michael Niedermayer

configure: add direct detection of libopencv

The pkg-config file contains all opencv libraries, not only the
neccessary ones.

This change makes it possible to use the libopencv-imgproc-dev Debian
package instead of libopencv-dev, saving about 200 MB of useless
build-dependencies.

In particular one doesn't need to install the parts of opencv that
depend on ffmpeg libraries.

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
Reviewed-by: James Almer <jamrial at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=15708f13477aaf2effdc0d7fc727507bc468335a
---

 configure |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index f4b821a..f28aa8f 100755
--- a/configure
+++ b/configure
@@ -5566,7 +5566,8 @@ enabled libnut            && require libnut libnut.h nut_demuxer_init -lnut
 enabled libopencore_amrnb && require libopencore_amrnb opencore-amrnb/interf_dec.h Decoder_Interface_init -lopencore-amrnb
 enabled libopencore_amrwb && require libopencore_amrwb opencore-amrwb/dec_if.h D_IF_init -lopencore-amrwb
 enabled libopencv         && { check_header opencv2/core/core_c.h &&
-                               require_pkg_config opencv opencv2/core/core_c.h cvCreateImageHeader ||
+                               { use_pkg_config opencv opencv2/core/core_c.h cvCreateImageHeader ||
+                                 require opencv opencv2/core/core_c.h cvCreateImageHeader -lopencv_core -lopencv_imgproc; } ||
                                require_pkg_config opencv opencv/cxcore.h cvCreateImageHeader; }
 enabled libopenh264       && require_pkg_config openh264 wels/codec_api.h WelsGetCodecVersion
 enabled libopenjpeg       && { check_lib openjpeg-2.1/openjpeg.h opj_version -lopenjp2 -DOPJ_STATIC ||