errors of 'vaGetDisplay' and `vaGetDisplayDRM'
<p>After updating my ubuntu OS from 14.04 to 16.04, I installed the ffmpeg library using the following configurations:</p>

<pre><code>PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure \
  --prefix="$HOME/ffmpeg_build" \
  --pkg-config-flags="--static" \
  --extra-cflags="-I$HOME/ffmpeg_build/include" \
  --extra-ldflags="-L$HOME/ffmpeg_build/lib" \
  --bindir="$HOME/bin" \
  --enable-gpl \
  --enable-libass \
  --enable-libfdk-aac \
  --enable-libfreetype \
  --enable-libmp3lame \
  --enable-libopus \
  --enable-libtheora \
  --enable-libvorbis \
  --enable-libvpx \
  --enable-libx264 \
  --enable-nonfree
PATH="$HOME/bin:$PATH" make
make install
</code></pre>

<p>It seemed to me the installation process was ok. After that, I tried to compile my own C source code with the following Makefile:</p>

<p><strong>EDITTED</strong>(adding -lva-drm -lva-x11 at line 10)</p>

<pre><code>FFMPEG_LIBS=    libavdevice                        \
                libavformat                        \
                libavfilter                        \
                libavcodec                         \
                libswresample                      \
                libswscale                         \
                libavutil                          \

TARGET = video_analysis
LIBS = -lva -lX11 -lvdpau -lm -lva-drm -lva-x11
CC = gcc
CFLAGS += -O2 -g -O0
CFLAGS := $(shell pkg-config --cflags $(FFMPEG_LIBS)) $(CFLAGS)
LDLIBS := $(shell pkg-config --libs $(FFMPEG_LIBS)) $(LDLIBS)

.PHONY: default all clean

default: $(TARGET)
all: default

OBJECTS = $(patsubst %.c, %.o, $(wildcard *.c))
HEADERS = $(wildcard *.h)

%.o: %.c $(HEADERS)
        $(CC) $(CFLAGS) -c $&lt; -o $@

.PRECIOUS: $(TARGET) $(OBJECTS)

$(TARGET): $(OBJECTS)
    $(CC) $(OBJECTS) $(LDLIBS) $(LIBS) -o $@

clean:
    -rm -f *.o
    -rm -f $(TARGET)
</code></pre>

<p>However, my compiler complained the following errors:</p>

<pre><code>/root/ffmpeg_build/lib/libavutil.a(hwcontext_vaapi.o): In function `vaapi_device_create':
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:896: undefined reference to `vaGetDisplay'
/home/widerstand/ffmpeg_sources/ffmpeg/libavutil/hwcontext_vaapi.c:917: undefined reference to `vaGetDisplayDRM'
collect2: error: ld returned 1 exit status
Makefile:30: recipe for target 'video_analysis' failed
make: *** [video_analysis] Error 1
</code></pre>

<p>My question is: in which library do 'vaGetDisplay' and `vaGetDisplayDRM' exist? It's for sure that libva functions properly. I have no clue how to fix the bugs...Thank you in advance!</p>