Windows building with all cores from powershell build script

README.md

@@ -55,7 +55,7 @@ mkdir build-dir
 cd build-dir
 $env:Path = "C:\Qt\Tools\mingw810_64\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Qt\Tools\Ninja;"
 C:\Qt\Tools\CMake_64\bin\cmake.exe -S .. -B . -GNinja "-DCMAKE_BUILD_TYPE:STRING=Release" "-DCMAKE_PROJECT_INCLUDE_BEFORE:PATH=C:/Qt/Tools/QtCreator/share/qtcreator/package-manager/auto-setup.cmake" "-DQT_QMAKE_EXECUTABLE:STRING=C:/Qt/6.2.1/mingw81_64/bin/qmake.exe" "-DCMAKE_PREFIX_PATH:STRING=C:/Qt/6.2.1/mingw81_64" "-DCMAKE_C_COMPILER:STRING=C:/Qt/Tools/mingw810_64/bin/gcc.exe" "-DCMAKE_CXX_COMPILER:STRING=C:/Qt/Tools/mingw810_64/bin/g++.exe"
-C:\Qt\Tools\CMake_64\bin\cmake.exe --build . --target all
+C:\Qt\Tools\CMake_64\bin\cmake.exe --build . --target all -- -j $((Get-CimInstance Win32_ComputerSystem).NumberOfLogicalProcessors)
 mv .\simple-process-tracker.exe ..
 rm -Recurse *
 mv ..\simple-process-tracker.exe .