ccanlint: tighten license check.

Now we've made GPL wording uniform, use it everywhere.  There's no
point allowing variants which might be unclear.

We still have some non-conformant licenses in the tree (eg. just "BSD"),
so we only warn on unknown license strings for now.

tools/ccanlint/tests/license_exists.c

@@ -25,33 +25,37 @@ static struct doc_section *find_license_tag(const struct manifest *m)
 	return NULL;
 }
 
+/* See GPLv2 and v2 (basically same wording) for interpreting versions:
+ * the "any later version" means the recepient can choose. */
 static enum license which_license(struct doc_section *d)
 {
-	if (strstarts(d->lines[0], "GPL")) {
-		if (strchr(d->lines[0], '3'))
-			return LICENSE_GPLv3;
-		else if (strchr(d->lines[0], '2')) {
-			if (strreg(NULL, d->lines[0], "or (any )?later", NULL))
-				return LICENSE_GPLv2_PLUS;
-			else
-				return LICENSE_GPLv2;
-		}
+	/* This means "user chooses what version", including GPLv1! */
+	if (streq(d->lines[0], "GPL"))
 		return LICENSE_GPL;
-	}
-
-	if (strstarts(d->lines[0], "LGPL")) {
-		if (strchr(d->lines[0], '3'))
-			return LICENSE_LGPLv3;
-		else if (strchr(d->lines[0], '2')) {
-			if (strreg(NULL, d->lines[0], "or (any )?later", NULL))
-				return LICENSE_LGPLv2_PLUS;
-			else
-				return LICENSE_LGPLv2;
-		}
+	/* This means "v2 only". */
+	if (streq(d->lines[0], "GPLv2"))
+		return LICENSE_GPLv2;
+	/* This means "v2 or above" at user's choice. */
+	if (streq(d->lines[0], "GPL (v2 or any later version)"))
+		return LICENSE_GPLv2_PLUS;
+	/* This means "v3 or above" at user's choice. */
+	if (streq(d->lines[0], "GPL (v3 or any later version)"))
+		return LICENSE_GPLv3;
+
+	/* This means "user chooses what version" */
+	if (streq(d->lines[0], "LGPL"))
 		return LICENSE_LGPL;
-	}
-	if (streq(d->lines[0], "BSD-MIT")
-	    || streq(d->lines[0], "MIT"))
+	/* This means "v2.1 only". */
+	if (streq(d->lines[0], "LGPLv2.1"))
+		return LICENSE_LGPLv2;
+	/* This means "v2.1 or above" at user's choice. */
+	if (streq(d->lines[0], "LGPL (v2.1 or any later version)"))
+		return LICENSE_LGPLv2_PLUS;
+	/* This means "v3 or above" at user's choice. */
+	if (streq(d->lines[0], "LGPL (v3 or any later version)"))
+		return LICENSE_LGPLv3;
+
+	if (streq(d->lines[0], "BSD-MIT") || streq(d->lines[0], "MIT"))
 		return LICENSE_MIT;
 	if (streq(d->lines[0], "BSD (3 clause)"))
 		return LICENSE_BSD;
@@ -129,6 +133,14 @@ static void check_has_license(struct manifest *m,
 	}
 
 	m->license = which_license(d);
+	if (m->license == LICENSE_UNKNOWN) {
+		score_file_error(score, m->info_file, d->srcline,
+				 "WARNING: unknown License: in _info: %s",
+				 d->lines[0]);
+		/* FIXME: For historical reasons, don't fail here. */
+		score->pass = true;
+		return;
+	}
 
 	/* If they have a license tag at all, we pass. */
 	score->pass = true;