replace various find_if calls

C++11 has shorter equivalents.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/option_parser.cc

@@ -88,7 +88,7 @@ bool
 OptionParser::has_flag(char flag, int argc, char** argv) {
   char options[3] = { '-', flag, '\0' };
 
-  return std::find_if(argv, argv + argc, [&options](char* c) { return std::strcmp(c, options) == 0; }) != argv + argc;
+  return std::any_of(argv, argv + argc, [&options](char* c) { return std::strcmp(c, options) == 0; });
 }
 
 std::string