Use execvpe instead of execve in omnitrace-sample (#187)

* Use execvpe instead of execve in omnitrace-sample

- previous implementation preferred exe in PATH over exe in PWD
- 'p' variants of exec duplicate the actions of the shell in searching for an executable file if the specified filename does not contain a slash character

* OpenMPI oversubscribe arg in testing

source/bin/omnitrace-sample/impl.cpp

@@ -64,12 +64,6 @@ auto updated_envs  = std::set<std::string_view>{};
 auto original_envs = std::set<std::string>{};
 }  // namespace
 
-std::string
-get_command(const char* _argv0)
-{
-    return omnitrace::path::find_path(_argv0, 0, omnitrace::common::get_env("PATH", ""));
-}
-
 std::string
 get_realpath(const std::string& _v)
 {

source/bin/omnitrace-sample/omnitrace-sample.cpp

@@ -56,11 +56,10 @@ main(int argc, char** argv)
 
     if(!_argv.empty())
     {
-        std::string _argv0 = get_command(_argv[0]);
         print_command(_argv);
         _argv.emplace_back(nullptr);
         _env.emplace_back(nullptr);
 
-        return execve(_argv0.c_str(), _argv.data(), _env.data());
+        return execvpe(_argv.front(), _argv.data(), _env.data());
     }
 }

source/bin/omnitrace-sample/omnitrace-sample.hpp

@@ -26,9 +26,6 @@
 #include <string_view>
 #include <vector>
 
-std::string
-get_command(const char*);
-
 std::string
 get_realpath(const std::string&);