gcc -D'SVN_REV="Unversioned directory"' -O2 -DLINUX -D_GNU_SOURCE -Wall    -c -o mjpg_streamer.o mjpg_streamer.c
In file included from mjpg_streamer.h:42:0,
                 from mjpg_streamer.c:42:
plugins/input.h:46:25: error: field ‘format’ has incomplete type
     struct v4l2_fmtdesc format;
                         ^
plugins/input.h:65:33: error: field ‘jpegcomp’ has incomplete type
     struct v4l2_jpegcompression jpegcomp;
                                 ^
In file included from mjpg_streamer.c:42:0:
mjpg_streamer.h:66:27: error: field ‘ctrl’ has incomplete type
     struct v4l2_queryctrl ctrl;
                           ^
<builtin>: recipe for target 'mjpg_streamer.o' failed
make: *** [mjpg_streamer.o] Error 1

reference to undefined identifier: gcc