ncd: add static strings "true" and "false"

ncd/NCDStringIndex.c

@@ -72,7 +72,9 @@ static const char *static_strings[] = {
     "_arg16",
     "_arg17",
     "_arg18",
-    "_arg19"
+    "_arg19",
+    "true",
+    "false"
 };
 
 static NCD_string_id_t do_get (NCDStringIndex *o, const char *str, size_t str_len)

ncd/static_strings.h

@@ -53,7 +53,9 @@ enum {
     NCD_STRING_ARG16,
     NCD_STRING_ARG17,
     NCD_STRING_ARG18,
-    NCD_STRING_ARG19
+    NCD_STRING_ARG19,
+    NCD_STRING_TRUE,
+    NCD_STRING_FALSE
 };
 
 #endif