diff --git a/configure.ac b/configure.ac
index 1d91c36e..13507d46 100644
--- a/configure.ac
+++ b/configure.ac
@@ -75,7 +75,7 @@ AC_HEADER_STAT
 AC_HEADER_TIME
 AC_CHECK_HEADERS([stdlib.h locale.h unistd.h limits.h fcntl.h string.h \
                   memory.h sys/param.h sys/resource.h sys/time.h sys/timeb.h \
-                  sys/select.h sys/file.h])
+                  sys/select.h sys/file.h spawn.h])
 
 AM_PROG_CC_C_O
 AC_C_CONST
@@ -142,7 +142,7 @@ AC_CHECK_FUNCS([strdup strndup umask mkstemp mktemp fdopen \
                 dup dup2 getcwd realpath sigsetmask sigaction \
                 getgroups seteuid setegid setlinebuf setreuid setregid \
                 getrlimit setrlimit setvbuf pipe strerror strsignal \
-                lstat readlink atexit isatty ttyname pselect])
+                lstat readlink atexit isatty ttyname pselect posix_spawn])
 
 # We need to check declarations, not just existence, because on Tru64 this
 # function is not declared without special flags, which themselves cause