diff --git a/configure.in b/configure.in
index e48e9e39..92434ec7 100644
--- a/configure.in
+++ b/configure.in
@@ -160,10 +160,12 @@ AC_FUNC_STRFTIME
 
 AC_CHECK_FUNCS([ \
 	bind gethostbyaddr gethostbyname gethostname inet_ntoa \
-	setsid setsockopt socket strcasecmp waitpid],,AC_MSG_ERROR([required function missing!]))
+	setsid setsockopt socket strcasecmp waitpid],,
+	AC_MSG_ERROR([required function missing!]))
 
-AC_CHECK_FUNCS(getaddrinfo getnameinfo inet_aton sigaction sigprocmask snprintf \
- vsnprintf strdup strlcpy strlcat strtok_r)
+AC_CHECK_FUNCS([ \
+	gai_strerror getaddrinfo getnameinfo inet_aton sigaction \
+	sigprocmask snprintf vsnprintf strdup strlcpy strlcat strtok_r])
 
 # -- Configuration options --
 
diff --git a/src/portab/portab.h b/src/portab/portab.h
index a75aa34d..90f36a0e 100644
--- a/src/portab/portab.h
+++ b/src/portab/portab.h
@@ -164,6 +164,10 @@ extern char * strtok_r PARAMS((char *str, const char *delim, char **saveptr));
 extern int vsnprintf PARAMS(( char *str, size_t count, const char *fmt, va_list args ));
 #endif
 
+#ifndef HAVE_GAI_STRERROR
+#define gai_strerror(r) "unknown error"
+#endif
+
 #ifndef PACKAGE_NAME
 #define PACKAGE_NAME PACKAGE
 #endif