add pledge(2) and unveil(2) to codebrowser_indexgenerator.

Index: indexgenerator/indexer.cpp
--- indexgenerator/indexer.cpp.orig
+++ indexgenerator/indexer.cpp
@@ -28,6 +28,8 @@
 #include <map>
 #include <ctime>
 
+#include <unistd.h>
+
 #include "../global.h"
 
 const char *data_url = "../data";
@@ -228,6 +230,14 @@ int main(int argc, char **argv) {
     if (root.empty()) {
         std::cerr << "Usage: " << argv[0] << " <path> [-d data_url] [-p project_definition]" << std::endl;
         return -1;
+    }
+    if ((unveil(root.c_str(), "rwc") == -1) || (unveil("/", "r") == -1)) {
+        std::cerr << "error: unveil" << std::endl;
+        return EXIT_FAILURE;
+    }
+    if (pledge("stdio rpath wpath cpath tty", "") == -1) {
+        std::cerr << "error: pledge" << std::endl;
+        return EXIT_FAILURE;
     }
     std::ifstream fileIndex(root + "/" + "fileIndex");
     std::string line;