BUG #11397: enable-profiling hangs configure at thread safety checking

The following bug has been logged on the website:

Bug reference: 11397
Logged by: Jov
Email address: amutu(at)amutu(dot)com
PostgreSQL version: 9.3.5
Operating system: FreeBSD r10 amd64
Description:

I configure PG with this cmd,and configure hangs:
./configure --enable-debug --enable-profiling --enable-cassert
--able-dtrace

....
checking for collateindex.pl... no
checking for xsltproc... no
checking for osx... no
checking for sgml2xml... no
checking for sx... no
checking thread safety of required library functions...
load: 0.58 cmd: conftest 25565 [umtxn] 34.63r 0.00u 0.00s 0% 3244k
load: 0.42 cmd: conftest 25565 [umtxn] 58.06r 0.00u 0.00s 0% 3244k
^[[B
load: 0.23 cmd: conftest 25565 [umtxn] 89.09r 0.00u 0.00s 0% 3244k

If I remove the enable-profiling option,the configure goes well.

some more info:
jovz ~]$ ps auxwww | grep conftest
jovz 30276 0.0 0.2 30804 3260 0 I+ 9:14下午 0:00.01 ./conftest
jovz 30302 0.0 0.1 18724 2348 1 S+ 9:16下午 0:00.01 grep conftest
[jovz ~]$ procstat -kk 30276
PID TID COMM TDNAME KSTACK

30276 100087 conftest - mi_switch+0xde
sleepq_catch_signals+0xb2 sleepq_wait_sig+0xf _sleep+0x265 umtxq_sleep+0x129
do_lock_umutex+0x64f __umtx_op_wait_umutex+0x78 amd64_syscall+0x357
Xfast_syscall+0xfb