Compile files do to pthread undefined reference

[km@…]

My build of the trunk as started failing with the error below. Presumably there is a missing link to the pthread library routines. This began some time after 05/05/2012 and 05/12/2012.

make[1]: Entering directory `/home/km/mythgit/mythtv/mythtv/external/FFmpeg' LD ffmpeg_g libavformat/libmythavformat.so: undefined reference to `pthread_create' libavformat/libmythavformat.so: undefined reference to `pthread_cancel' libavformat/libmythavformat.so: undefined reference to `pthread_join' collect2: ld returned 1 exit status make[1]: * [ffmpeg_g] Error 1 make[1]: Leaving directory `/home/km/mythgit/mythtv/mythtv/external/FFmpeg' make: * [external/FFmpeg] Error 2