Using Precompiled headers for Linux (WSL) development in Visual Studio

precompile.sh

#!/bin/sh

gch="src/stdafx.h.gch"
header="src/stdafx.h"

function compile
{
	echo "Generating precompiled header.."
	
	# IMPORTANT: Make sure to edit this so it has all the required flags!
	g++ -c -x c++-header stdafx.cpp -o stdafx.h.gch 
}

if [[ -f $gch ]]; then # File exists
  if [[ $header -nt $gch ]]; then
	compile
  else 
	echo "Precompiled header already exists.."
  fi
else 
	compile
fi

Precompiled Headers Linux (Visual Studio 2019)

Precompiled headers basically improve build times by reducing the amount of code compiling each time a build 
command is invoked.
This feature is available in Visual Studio for Windows C/C++ development 
via project "Properties" -> "C/C++" -> "Precompiled Headers", 
but this feature is missing for Linux C/C++ Development (Visual Studio) and 
requires a workaround since GCC/Clang support pch.

The workaround:
- Creating a "precompile.sh" bash script and appending the content above.
- Set in your project's properties in "Properties" -> "Build Events" -> "WSL Pre-Build Event", the following:
  1. Command Line: sh precompile.sh
  2. Use In Build: Yes
  
 This will basically launch every time a build command is invoked, the header file date will be checked, 
 if the header is newer than the pch (precompiled header) or the pch is missing, it will (re)compile the header and 
 continue with the build process.
 
 Credits: https://developercommunity.visualstudio.com/t/linux-builds-add-precompiled-headers-support/569226