Add own memmove() implementation

This is required for SunOS 4.1.4 aka Solaris 1.1.
Thanks to Götz Hoffart for testing!

configure.ng

@@ -207,10 +207,8 @@ AC_CHECK_MEMBER([struct sockaddr_in.sin_len], AC_DEFINE(HAVE_sockaddr_in_len),,
 
 # -- Libraries --
 
-# memmove: A/UX libUTIL
-AC_SEARCH_LIBS([memmove], [UTIL], [], [
-	AC_MSG_ERROR([unable to find the memmove() function])
-])
+# memmove: A/UX libUTIL; but we can use our own implementation.
+AC_SEARCH_LIBS([memmove], [UTIL])
 # gethostbyname: Solaris libnsl
 AC_SEARCH_LIBS([gethostbyname], [bind nsl network], [], [
 	AC_MSG_ERROR([unable to find the gethostbyname() function])
@@ -235,7 +233,6 @@ AC_CHECK_FUNCS([ \
 		gethostname \
 		gettimeofday \
 		inet_ntoa \
-		memmove \
 		memset \
 		setsid \
 		socket \
@@ -257,6 +254,7 @@ AC_CHECK_FUNCS_ONCE([
 	gai_strerror \
 	getnameinfo \
 	inet_aton \
+	memmove \
 	setgroups \
 	sigaction \
 	sigprocmask \

src/portab/Makefile.ng

@@ -16,6 +16,7 @@ EXTRA_DIST = Makefile.ng
 noinst_LIBRARIES = libngportab.a
 
 libngportab_a_SOURCES = \
+	memmove.c \
 	strdup.c \
 	strlcpy.c \
 	strndup.c \

src/portab/memmove.c

@@ -0,0 +1,33 @@
+/*
+ * ngIRCd -- The Next Generation IRC Daemon
+ */
+
+#include "portab.h"
+
+/**
+ * @file
+ * memmove() implementation.
+ * Source: http://c-faq.com/~scs/cgi-bin/faqcat.cgi?sec=ansi
+ */
+
+#ifndef HAVE_MEMMOVE
+
+GLOBAL void *
+memmove(void *dest, void const *src, size_t n)
+{
+	register char *dp = dest;
+	register char const *sp = src;
+	if(dp < sp) {
+		while(n-- > 0)
+			*dp++ = *sp++;
+	} else {
+		dp += n;
+		sp += n;
+		while(n-- > 0)
+			*--dp = *--sp;
+	}
+
+	return dest;
+}
+
+#endif