added like operator and handling of string sargs

Added index stuff to HACKING file
Misc. mdb-sql updates

src/libmdb/like.c

@@ -0,0 +1,38 @@
+#include <stdio.h>
+
+int likecmp(char *s, char *r)
+{
+int i, ret;
+
+	switch (r[0]) {
+		case '\0':
+			if (s[0]=='\0') {
+				return 1;
+			} else {
+				return 0;
+			}
+		case '_':
+			/* skip one character */
+			return likecmp(&s[1],&r[1]);
+		case '%':
+			/* skip any number of characters */
+			/* the strlen(s)+1 is important so the next call can */
+			/* if there are trailing characters */
+			for(i=0;i<strlen(s)+1;i++) {
+				if (likecmp(&s[i],&r[1])) {
+					return 1;
+				}
+			}
+			return 0;
+		default:
+			for(i=0;i<strlen(r);i++) {
+				if (r[i]=='_' || r[i]=='%') break;
+			}
+			if (strncmp(s,r,i)) {
+				return 0;
+			} else {
+				ret = likecmp(&s[i],&r[i]);
+				return ret;
+			}
+	}
+}