ccanlint - avoid e.g. GPL vs LGPL mismatch in license checking

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tools/ccanlint/tests/license_comment.c

@@ -11,6 +11,40 @@
 #include <err.h>
 #include <ccan/str/str.h>
 
+static char *xstrdup(const char *s) {
+	char * ret = strdup(s);
+	if (ret == NULL) {
+		perror("strdup");
+		abort();
+	}
+	return ret;
+}
+
+/**
+ * line_has_license_flavour - returns true if line contains a <flavour> license
+ * @line: line to look for license in
+ * @shortname: license to find
+ * @note ("LGPLv2.0","LGPL") returns true
+ * @note ("LGPLv2.0","GPL") returns false
+ */
+static bool line_has_license_flavour(const char *line, const char *flavour) {
+	char *strtok_line, *strtok_tmp, *token;
+	bool ret = false;
+	const size_t flavour_len = strlen(flavour);
+
+	strtok_line = strtok_tmp = xstrdup(line);
+	while((token = strtok(strtok_tmp, " \t-:")) != NULL) {
+		if (!strncmp(token, flavour, flavour_len)) {
+			ret = true;
+			break;
+		}
+		strtok_tmp = NULL;
+	}
+	free(strtok_line);
+
+	return ret;
+}
+
 static void check_license_comment(struct manifest *m,
 				  unsigned int *timeleft, struct score *score)
 {
@@ -38,8 +72,8 @@ static void check_license_comment(struct manifest *m,
 					break;
 				if (strstr(lines[i], "LICENSE"))
 					found_license = true;
-				if (strstr(lines[i],
-					   licenses[m->license].shortname))
+				if (line_has_license_flavour(lines[i],
+							     licenses[m->license].shortname))
 					found_flavor = true;
 			}
 			if ((!found_license || !found_flavor)