diff --git a/configure.ac b/configure.ac
index 96b9d43..529482d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -83,7 +83,7 @@ AM_CONDITIONAL([STATIC], [test "x$static" = "xyes"])
 AC_CHECK_HEADERS(fcntl.h sys/time.h unistd.h sys/mman.h)
 AC_CHECK_HEADERS(ctype.h errno.h sys/resource.h)
 AC_CHECK_HEADERS(endian.h sys/endian.h arpa/inet.h)
-AC_CHECK_HEADERS(alloca.h)
+AC_CHECK_HEADERS(alloca.h pthread.h)
 
 AC_TYPE_OFF_T
 AC_TYPE_SIZE_T
diff --git a/lrzip_private.h b/lrzip_private.h
index 72225b1..92240b8 100644
--- a/lrzip_private.h
+++ b/lrzip_private.h
@@ -30,6 +30,11 @@
 #include <stdio.h>
 #include <stdbool.h>
 #include <stdarg.h>
+
+#ifdef HAVE_PTHREAD_H
+# include <pthread.h>
+#endif
+
 #ifdef HAVE_STRING_H
 # include <string.h>
 #endif