cannot compile on hpux

I have ./configure and then make.

This is the error returned by the compiling process:

Making all in src/main
/bin/sh ../../libtool --tag=CXX --mode=compile g++ -DHAVE_CONFIG_H -I. -I../.. -ansi -pedantic -DHPUX11 -D_REENTRANT -D_HPUX_SOURCE -D_LARGEFILE64_SOURCE -I/diap6/home/jaeco/dev-root/usr/include/apr-1 -I/usr/local/include -W -Wall -Wextra -Wconversion -fPIC -fstrict-aliasing -Wstrict-aliasing=2 -Wno-long-long -g -O2 -pthread -MT decaf/internal/util/concurrent/unix/libactivemq_cpp_la-PlatformThread.lo -MD -MP -MF decaf/internal/util/concurrent/unix/.deps/libactivemq_cpp_la-PlatformThread.Tpo -c -o decaf/internal/util/concurrent/unix/libactivemq_cpp_la-PlatformThread.lo `test -f 'decaf/internal/util/concurrent/unix/PlatformThread.cpp' || echo './'`decaf/internal/util/concurrent/unix/PlatformThread.cpp
libtool: compile: g++ -DHAVE_CONFIG_H -I. -I../.. -ansi -pedantic -DHPUX11 -D_REENTRANT -D_HPUX_SOURCE -D_LARGEFILE64_SOURCE -I/diap6/home/jaeco/dev-root/usr/include/apr-1 -I/usr/local/include -W -Wall -Wextra -Wconversion -fPIC -fstrict-aliasing -Wstrict-aliasing=2 -Wno-long-long -g -O2 -pthread -MT decaf/internal/util/concurrent/unix/libactivemq_cpp_la-PlatformThread.lo -MD -MP -MF decaf/internal/util/concurrent/unix/.deps/libactivemq_cpp_la-PlatformThread.Tpo -c decaf/internal/util/concurrent/unix/PlatformThread.cpp -fPIC -DPIC -o decaf/internal/util/concurrent/unix/.libs/libactivemq_cpp_la-PlatformThread.o
decaf/internal/util/concurrent/unix/PlatformThread.cpp: In static member function 'static void decaf::internal::util::concurrent::PlatformThread::yeild()':
decaf/internal/util/concurrent/unix/PlatformThread.cpp:450: error: 'pthread_yield' was not declared in this scope

• • • Error exit code 1

Stop.

• • • Error exit code 1

Stop.

• • • Error exit code 1