test(profiling): improve native tests (#16377)

## Description

As title says, this is just a quality of life improvement PR:
- Runs native tests in parallel 
- Fixes warnings reported by CMake when building.

Author: KowalskiThomas

ddtrace/internal/datadog/profiling/build_standalone.sh

@@ -192,7 +192,12 @@ run_cmake() {
   fi
   if [[ " ${cmake_args[*]} " =~ " -DBUILD_TESTING=ON " ]]; then
     echo "--------------------------------------------------------------------- Running Tests"
-    ctest ${ctest_args[*]} --output-on-failure || { echo "tests failed!"; exit 1; }
+    if command -v nproc &> /dev/null; then
+      NPROC=$(nproc)
+    else
+      NPROC=$(getconf _NPROCESSORS_ONLN)
+    fi
+    ctest -j${NPROC} ${ctest_args[*]} --output-on-failure || { echo "tests failed!"; exit 1; }
   fi
 
   # OK, the build or whatever went fine I guess.

ddtrace/internal/datadog/profiling/dd_wrapper/CMakeLists.txt

@@ -33,12 +33,14 @@ set(CMAKE_VERBOSE_MAKEFILE ON)
 
 # Since this file is currently only loaded as a subdirectory, we need to propagate certain libdatadog variables up to
 # the parent scope.
-set(Datadog_INCLUDE_DIRS
-    ${Datadog_INCLUDE_DIRS}
-    PARENT_SCOPE)
-set(Datadog_LIBRARIES
-    ${Datadog_LIBRARIES}
-    PARENT_SCOPE)
+if(NOT CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+    set(Datadog_INCLUDE_DIRS
+        ${Datadog_INCLUDE_DIRS}
+        PARENT_SCOPE)
+    set(Datadog_LIBRARIES
+        ${Datadog_LIBRARIES}
+        PARENT_SCOPE)
+endif()
 
 set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)

ddtrace/internal/datadog/profiling/dd_wrapper/test/CMakeLists.txt

@@ -60,7 +60,9 @@ function(dd_wrapper_add_test name)
                    ENVIRONMENT "TSAN_OPTIONS=die_after_fork=0:suppressions=${CMAKE_CURRENT_SOURCE_DIR}/TSan.supp")
 
     if(LIB_INSTALL_DIR)
-        install(TARGETS ${name} RUNTIME DESTINATION ${LIB_INSTALL_DIR}/../test)
+        get_filename_component(_test_install_dir "${LIB_INSTALL_DIR}" DIRECTORY)
+        set(_test_install_dir "${_test_install_dir}/test")
+        install(TARGETS ${name} RUNTIME DESTINATION ${_test_install_dir})
     endif()
 endfunction()