--- a/configure.ac
+++ b/configure.ac
@@ -760,7 +760,7 @@ AC_CHECK_FUNCS([DINFINITY DQNAN cexp chsize clog clog10 ctermid		\
   sched_setaffinity sendfile])
 
 AM_CONDITIONAL([BUILD_ICE_9_POPEN],
-  [test "x$enable_posix" = "xyes" && test "x$ac_cv_func_fork" = "xyes"])
+  [test "x$enable_posix" = "xyes"])