test for alpine-2.22's c-client and cope with API change.
parts borrowed from slackware patch for PHP with alpine-2.22.

Index: apps/app_voicemail.c
--- apps/app_voicemail.c.orig
+++ apps/app_voicemail.c
@@ -60,6 +60,9 @@
 #include <c-client/c-client.h>
 #include <c-client/imap4r1.h>
 #include <c-client/linkage.h>
+#if defined (HAVE_IMAP_ALPINE2_22)
+char *cpystr(const char *str);	/* from c-client/misc.h but that has namespace problems */
+#endif
 #else
 #include "c-client.h"
 #include "imap4r1.h"
@@ -3305,7 +3308,11 @@ void mm_dlog(char *string)
 }
 
 
+#if defined(HAVE_IMAP_ALPINE2_22)
+void mm_login(NETMBX * mb, char *user, char **pwd, long trial)
+#else
 void mm_login(NETMBX * mb, char *user, char *pwd, long trial)
+#endif
 {
 	struct ast_vm_user *vmu;
 
@@ -3315,22 +3322,41 @@ void mm_login(NETMBX * mb, char *user, char *pwd, long
 
 	/* We should only do this when necessary */
 	if (!ast_strlen_zero(authpassword)) {
+#if defined(HAVE_IMAP_ALPINE2_22)
+		*pwd = cpystr(authpassword);
+#else
 		ast_copy_string(pwd, authpassword, MAILTMPLEN);
+#endif
 	} else {
 		AST_LIST_TRAVERSE(&users, vmu, list) {
 			if (!strcasecmp(mb->user, vmu->imapuser)) {
+#if defined(HAVE_IMAP_ALPINE2_22)
+				*pwd = cpystr(vmu->imappassword);
+#else
 				ast_copy_string(pwd, vmu->imappassword, MAILTMPLEN);
+#endif
 				break;
 			}
 		}
 		if (!vmu) {
 			if ((vmu = find_user_realtime_imapuser(mb->user))) {
+#if defined(HAVE_IMAP_ALPINE2_22)
+				*pwd = cpystr(vmu->imappassword);
+#else
 				ast_copy_string(pwd, vmu->imappassword, MAILTMPLEN);
+#endif
 				free_user(vmu);
 			}
 		}
 	}
 }
+
+#if defined(HAVE_IMAP_ALPINE2_22)
+void mm_login_method(NETMBX *mb, char *user, void *pwd, long trial, char *method)
+{
+   return;
+}
+#endif
 
 
 void mm_critical(MAILSTREAM * stream)