Speeding-up GitHub build-bots (#1392)

* disabling LTO when building the profiler on macos via the github workflow

* diagnosing where in the linking stage it's getting stuck

* fowrward declarations

* compilation time report

* trying clang build analyzer...

* reducing number of parallel workers

* limiting parallel workers on windows/linux as well

* re-enabling LTO on macos

* reverting forward declaration header include (emscripten is failing with them).

* reverting act changes

* removing comments

.github/workflows/linux.yml

@@ -32,7 +32,7 @@ jobs:
         if [ "${ACT:-}" != "true" ] && [ "${FORGEJO_ACTIONS:-}" != "true" ]; then
           cmake --build profiler/build
         else
-          cmake --build profiler/build --parallel
+          cmake --build profiler/build --parallel 2
         fi
     - name: Update utility
       run: |