diff --git a/lib/amigaos.c b/lib/amigaos.c
index b0a9500267..139309b116 100644
--- a/lib/amigaos.c
+++ b/lib/amigaos.c
@@ -178,6 +178,7 @@ struct Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname,
 #endif /* CURLRES_AMIGA */
 
 #ifdef USE_AMISSL
+#include <signal.h>
 int Curl_amiga_select(int nfds, fd_set *readfds, fd_set *writefds,
                       fd_set *errorfds, struct timeval *timeout)
 {