pthread-related build failure on Tru64

[Dave Love]

I get this on Tru64 5.1a:

gcc -DHAVE_CONFIG_H -I. -I. -I. -I/usr/local/BerkeleyDB.3.2/include 
-I/usr/local/ssl/include    -g -O2  -Wreturn-type -Wmissing-prototypes 
-Wuninitialized -c `test -f cfservd.c || echo './'`cfservd.c
cfservd.c: In function `SpawnConnection':
cfservd.c:798: `PTHREADDEFAULTS' undeclared (first use in this function)
cfservd.c:798: (Each undeclared identifier is reported only once
cfservd.c:798: for each function it appears in.)
cfservd.c:799: `PTHREAD_CREATE_DETACHED' undeclared (first use in this function)
cfservd.c:805: `tid' undeclared (first use in this function)
cfservd.c: In function `HandleConnection':
cfservd.c:988: `MUTEX_COUNT' undeclared (first use in this function)

config.log shows:

configure:6016: checking for pthread.h
configure:6026: gcc -E  conftest.c
In file included from configure:6023:
/usr/include/pthread.h:312:4: #error "Please compile the module including 
pthread.h with -pthread"

Configuring with `CCPFLAGS=-pthread' finds pthread.h and allows it to
compile.  I guess there's call for a specific autoconf macro for
this...