Move libc replacement files from src/backend/port to src/port.

src/port/strerror.c

@@ -0,0 +1,31 @@
+/* $Id: strerror.c,v 1.1 2002/07/18 04:13:59 momjian Exp $ */
+
+/*
+ * strerror - map error number to descriptive string
+ *
+ * This version is obviously somewhat Unix-specific.
+ *
+ * based on code by Henry Spencer
+ * modified for ANSI by D'Arcy J.M. Cain
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+extern const char *const sys_errlist[];
+extern int	sys_nerr;
+
+const char *
+strerror(int errnum)
+{
+	static char buf[24];
+
+	if (errnum < 0 || errnum > sys_nerr)
+	{
+		sprintf(buf, "unknown error %d", errnum);
+		return buf;
+	}
+
+	return sys_errlist[errnum];
+}