cmd:opts: Now set OptionParser::argv0 to argv[0]

hcore/include/opts.h

@@ -23,6 +23,7 @@ public:
     }
 
 public:
+    std::string argv0;
     std::string senseApiLibPath;
     std::vector<std::string> senseApiLibs;
     std::string deviceSpecs;

hcore/opts.cpp

@@ -25,6 +25,9 @@ void OptionParser::parseArguments(int argc, char *argv[])
 {
     int opt;
     int optionIndex = 0;
+
+    argv0 = argv[0];
+
     optind = 1; // Reset optind to 1 before parsing
     while ((opt = getopt_long(
         argc, argv, "s:d:a:p:v?", longOptions, &optionIndex)) != -1)
@@ -80,7 +83,7 @@ void OptionParser::parseArguments(int argc, char *argv[])
 
 std::string OptionParser::getUsage() const
 {
-    return "Usage: program [-s|--devicespec|--spec|--devspec <device_spec>] "
+    return "Usage: " + argv0 + " [-s|--devicespec|--spec|--devspec <device_spec>] "
            "[-d|--devfile|--devicefile <filename>] "
            "[-a|--sense-api-lib|--senseapi <filename>] "
            "[-p|--sense-api-path <directory>] "