Make some changes in the database schema:

1. Add columns for storing md5 checksum and machine architecture in
 the mandb table.
2. Update the DBSCHEMA file to reflect these changes and also remove
the UNIQUE constraint from the link column in mandb_links table,
which was wrong.
3. Add code in makemandb.c to store these two columns in mandb.
4. Give a weight of 0.0 to the md5_hash column in the ranking algorithm
as it should not affect the search results and weight of 1.0 to the
machine column.
Fixes #64

DBSCHEMA

@@ -15,9 +15,12 @@ There are three tables in the database at present:
   6. return_vals    RETURN VALUES section
   7. env            ENVIRONMENT section
   8. files          FILES section
-  9. exit_status   EXIT STATUS section
+  9. exit_status    EXIT STATUS section
   10. diagnostics   DIAGNOSTICS section
   11. errors        ERRORS section
+  12. md5_hash		md5 hash of the man page
+  13. machine		The machine architecture (if any) for which this page is
+                    relevant.
 
 (2) mandb_meta:
     This table contains md5 hashes of all the indexed man 
@@ -42,7 +45,7 @@ There are three tables in the database at present:
     from the multiple .Nm entries in the page.
 
   Column Name       Description
-  1. link           The name of the hard/soft link (UNIQUE index) 
+  1. link           The name of the hard/soft link (index) 
   2. target         Name of the target page to which it points  
   3. section        The section number  
   4. machine        The machine architecture (if any) for which 

apropos-utils.c

@@ -66,7 +66,9 @@ static const double col_weights[] = {
 	0.01,	//FILES
 	0.001,	//EXIT STATUS
 	2.00,	//DIAGNOSTICS
-	0.05	//ERRORS
+	0.05,	//ERRORS
+	0.00,	//md5_hash
+	1.00	//machine
 };
 
 /*
@@ -144,10 +146,11 @@ create_db(sqlite3 *db)
 
 	sqlstr = "CREATE VIRTUAL TABLE mandb USING fts4(section, name, "
 				"name_desc, desc, lib, return_vals, env, files, "
-				"exit_status, diagnostics, errors, compress=zip, "
-				"uncompress=unzip, tokenize=porter); "	//mandb table
-			"CREATE TABLE IF NOT EXISTS mandb_meta(device, inode, mtime, file UNIQUE, "
-				"md5_hash UNIQUE, id  INTEGER PRIMARY KEY); "	//mandb_meta
+				"exit_status, diagnostics, errors, md5_hash, machine, "
+				"tokenize=porter); "	//mandb
+			"CREATE TABLE IF NOT EXISTS mandb_meta(device, inode, mtime, "
+			"file UNIQUE, md5_hash UNIQUE, id  INTEGER PRIMARY KEY); "
+				//mandb_meta
 			"CREATE TABLE IF NOT EXISTS mandb_links(link, target, section, "
 				"machine); ";	//mandb_links
 

makemandb.c

@@ -1353,7 +1353,7 @@ insert_into_db(sqlite3 *db, mandb_rec *rec)
 /*------------------------ Populate the mandb table---------------------------*/
 	sqlstr = "INSERT INTO mandb VALUES (:section, :name, :name_desc, :desc, "
 			":lib, :return_vals, :env, :files, :exit_status, "
-			":diagnostics, :errors)";
+			":diagnostics, :errors, :md5_hash, :machine)";
 
 	rc = sqlite3_prepare_v2(db, sqlstr, -1, &stmt, NULL);
 	if (rc != SQLITE_OK) {
@@ -1460,6 +1460,24 @@ insert_into_db(sqlite3 *db, mandb_rec *rec)
 		cleanup(rec);
 		return -1;
 	}
+
+	idx = sqlite3_bind_parameter_index(stmt, ":md5_hash");
+	rc = sqlite3_bind_text(stmt, idx, rec->md5_hash, -1, NULL);
+	if (rc != SQLITE_OK) {
+		warnx("%s", sqlite3_errmsg(db));
+		sqlite3_finalize(stmt);
+		cleanup(rec);
+		return -1;
+	}
+
+	idx = sqlite3_bind_parameter_index(stmt, ":machine");
+	rc = sqlite3_bind_text(stmt, idx, rec->machine, -1, NULL);
+	if (rc != SQLITE_OK) {
+		warnx("%s", sqlite3_errmsg(db));
+		sqlite3_finalize(stmt);
+		cleanup(rec);
+		return -1;
+	}
 
 	rc = sqlite3_step(stmt);
 	if (rc != SQLITE_DONE) {