For some reason `pthread` is listed. I failed to see why this is not passed.
$ cat /usr/lib/i386-linux-gnu/pkgconfig/check.pc
prefix=/usr
exec_prefix=${prefix}
libdir=${prefix}/lib/i386-linux-gnu
includedir=${prefix}/include
Name: Check
Description: A unit test framework for C
URL: http://check.sourceforge.net
Version: 0.10.0
Requires: libsubunit
Libs: -L${libdir} -lcheck_pic -lrt -lm
Libs.private:
Cflags: -I${includedir} -pthread
