[analyzer] Warn about -analyzer-configs being meant for development purposes only

[Szelethus]

Summary

This is more of a temporary fix, long term, we should convert AnalyzerOptions.def into the universally beloved (*coughs*) TableGen format, where they can more easily be separated into developer-only, alpha, and user-facing configs.

[NoQ]

Thanks, i appreciate!

cfe/trunk/include/clang/Driver/CC1Options.td

HelpText<"Display the list of in development analyzer checkers. These "
            "are NOT considered safe, they are unstable and will emit incorrect "
            "reports. Enable ONLY FOR DEVELOPMENT purposes">;
 
 def analyzer_checker_help_developer : Flag<["-"], "analyzer-checker-help-developer">,
   HelpText<"Display the list of developer-only checkers such as modeling "
            "and debug checkers">;
 
 def analyzer_config_help : Flag<["-"], "analyzer-config-help">,
-  HelpText<"Display the list of -analyzer-config options">;
+  HelpText<"Display the list of -analyzer-config options. These are meant for "
+           "development purposes only!">;
 
 def analyzer_list_enabled_checkers : Flag<["-"], "analyzer-list-enabled-checkers">,
   HelpText<"Display the list of enabled analyzer checkers">;
 
 def analyzer_config : Separate<["-"], "analyzer-config">,
   HelpText<"Choose analyzer options to enable">;
 
 def analyzer_checker_option_help : Flag<["-"], "analyzer-checker-option-help">,

cfe/trunk/lib/StaticAnalyzer/Frontend/CheckerRegistration.cpp

void ento::printCheckerConfigList(raw_ostream &OS,
                                   AnalyzerOptions &opts,
                                   DiagnosticsEngine &diags,
                                   const LangOptions &LangOpts) {
   CheckerRegistry(plugins, diags, opts, LangOpts)
       .printCheckerOptionList(OS);
 }
 
 void ento::printAnalyzerConfigList(raw_ostream &out) {
-  out << "OVERVIEW: Clang Static Analyzer -analyzer-config Option List\n\n";
-  out << "USAGE: -analyzer-config <OPTION1=VALUE,OPTION2=VALUE,...>\n\n";
-  out << "       -analyzer-config OPTION1=VALUE, -analyzer-config "
-         "OPTION2=VALUE, ...\n\n";
-  out << "OPTIONS:\n\n";
+  // FIXME: This message sounds scary, should be scary, but incorrectly states
+  // that all configs are super dangerous. In reality, many of them should be
+  // accessible to the user. We should create a user-facing subset of config
+  // options under a different frontend flag.
+  out << R"(
+OVERVIEW: Clang Static Analyzer -analyzer-config Option List
+
+The following list of configurations are meant for development purposes only, as
+some of the variables they define are set to result in the most optimal
+analysis. Setting them to other values may drastically change how the analyzer
+behaves, and may even result in instabilities, crashes!
+
+USAGE: -analyzer-config <OPTION1=VALUE,OPTION2=VALUE,...>
+       -analyzer-config OPTION1=VALUE, -analyzer-config OPTION2=VALUE, ...
+OPTIONS:
+)";
 
   using OptionAndDescriptionTy = std::pair<StringRef, std::string>;
   OptionAndDescriptionTy PrintableOptions[] = {
 #define ANALYZER_OPTION(TYPE, NAME, CMDFLAG, DESC, DEFAULT_VAL)                \
     {                                                                          \
       CMDFLAG,                                                                 \
       llvm::Twine(llvm::Twine() + "(" +                                        \
                   (StringRef(#TYPE) == "StringRef" ? "string" : #TYPE ) +      \