musl doesn't recognise the alternate name for ascii
diff --git a/src/core/sip-sec-ntlm.c b/src/core/sip-sec-ntlm.c
index 2e2354f..7679e33 100644
--- a/src/core/sip-sec-ntlm.c
+++ b/src/core/sip-sec-ntlm.c
@@ -297,7 +297,7 @@ struct authenticate_message {
 #ifdef __sun__
 static char SIPE_DEFAULT_CODESET[] = "US-ASCII";
 #else
-static char SIPE_DEFAULT_CODESET[] = "ANSI_X3.4-1968";
+static char SIPE_DEFAULT_CODESET[] = "US-ASCII";
 #endif
 #endif