diff --git a/src/configure.in b/src/configure.in
index c0a60b2..43bf9ad 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -3598,7 +3598,7 @@
 	getpwent getpwnam getpwuid getrlimit gettimeofday getwd lstat memcmp \
 	memset mkdtemp nanosleep opendir putenv qsort readlink select setenv \
 	setpgid setsid sigaltstack sigstack sigset sigsetjmp sigaction \
-	sigvec strcasecmp strerror strftime stricmp strncasecmp \
+	sigprocmask sigvec strcasecmp strerror strftime stricmp strncasecmp \
 	strnicmp strpbrk strtol tgetent towlower towupper iswupper \
 	usleep utime utimes)
 AC_FUNC_FSEEKO