Attempting to statically link rpm against nptl from -34,
I get the following unresolved symbols with -L/usr/lib/nptl

/usr/lib/nptl/libpthread.a(lowlevelcond.o)(.text+0x5f): In function
`pthread_cond_wait':
: undefined reference to `__pthread_mutex_unlock_internal'
/usr/lib/nptl/libpthread.a(lowlevelcond.o)(.text+0x11b): In function
`pthread_cond_wait':
: undefined reference to `__pthread_mutex_lock_internal'
/usr/lib/nptl/libpthread.a(lowlevelcond.o)(.text+0x172): In function
`pthread_cond_timedwait':
: undefined reference to `__pthread_mutex_unlock_internal'
/usr/lib/nptl/libpthread.a(lowlevelcond.o)(.text+0x293): In function
`pthread_cond_timedwait':
: undefined reference to `__pthread_mutex_lock_internal'
collect2: ld returned 1 exit status

FWIW I don't see the symbols anywhere in /usr/lib/nptl/*.a nor in
/usr/include/{*.h,*/*.h}