Update build steps in README.md (#517)

README.md

@@ -16,20 +16,67 @@ git clone --recurse-submodules https://github.com/flightlessmango/MangoHud.git
 cd MangoHud
 ```
 
-To build it, execute:
+Using `meson` to install "manually":
 
 ```
-./build.sh build
-./build.sh package
+meson build
+ninja -C build install
 ```
 
-**NOTE: If you are running an Ubuntu-based, Arch-based, Fedora-based, or openSUSE-based distro, the build script will automatically detect and prompt you to install missing build dependencies. If you run into any issues with this please report them!**
+By default, meson should install MangoHud to `/usr/local`. Specify install prefix with `--prefix=/usr` if desired.
+Add `-Dappend_libdir_mangohud=false` option to meson to not append `mangohud` to libdir if desired (e.g. /usr/local/lib/mangohud).
+
+To install 32-bit build on 64-bit distro, specify proper `libdir`: `lib32` for Arch, `lib/i386-linux-gnu` on Debian. RPM-based distros usually install 32-bit libraries to `/usr/lib` and 64-bit to `/usr/lib64`.
+You may have to change `PKG_CONFIG_PATH` to point to correct folders for your distro.
+
+```
+CC="gcc -m32" \
+CXX="g++ -m32" \
+PKG_CONFIG_PATH="/usr/lib32/pkgconfig:/usr/lib/i386-linux-gnu/pkgconfig:/usr/lib/pkgconfig" \
+meson build32 --libdir lib32
+ninja -C build32 install
+```
+
+### Dependencies
+
+Install necessary development packages.
+
+- gcc, g++
+- or gcc-multilib, g++-multilib for 32-bit support
+- meson >=0.54
+- ninja (ninja-build)
+- glslang
+- vulkan headers if using `-Duse_system_vulkan=enabled` option with `meson`
+- libGL/libEGL (libglvnd, mesa-common-dev, mesa-libGL-devel etc)
+- X11 (libx11-dev)
+- libdrm (libdrm-dev)
+- XNVCtrl (libxnvctrl-dev), optional, use `-Dwith_xnvctrl=disabled` option with `meson` to disable
+- D-Bus (libdbus-1-dev), optional, use `-Dwith_dbus=disabled` option with `meson` to disable
+
+Python 3 libraries:
+
+- Mako (python3-mako or install with `pip`)
+
+
+If distro's packaged `meson` is too old and gives build errors, install newer version with `pip` (`python3-pip`).
+
+### Building with build script
+
+You can also use `build.sh` script to do some things automatically like install dependencies, if distro is supported but it usually assumes you are running on x86_64 architecture.
+
+To just build it, execute:
+
+```
+./build.sh build
+```
 
-Once done, proceed to the [installation](#source).
+You can also pass arguments to meson:
 
-## Install
+```
+./build.sh build -Dwith_xnvctrl=disabled
+```
 
-### Source
+Resulting files will be install to `./build/release` folder.
 
 If you have compiled MangoHud from source, to install it, execute:
 
@@ -43,6 +90,29 @@ You can then subsequently uninstall MangoHud via the following command
 ./build.sh uninstall
 ```
 
+To tar up the resulting binaries into a package and create a release tar with installer script, execute:
+
+```
+./build.sh package release
+```
+
+or combine the commands, although `package` should also call `build` if it doesn't find the built libs:
+
+```
+./build.sh build package release
+```
+
+If you have built MangoHud before and suddenly it fails, you can try cleaning the `build` folder, execute:
+
+```
+./build.sh clean
+```
+
+Currently it just does `rm -fr build` and clears subprojects.
+
+**NOTE: If you are running an Ubuntu-based, Arch-based, Fedora-based, or openSUSE-based distro, the build script will automatically detect and prompt you to install missing build dependencies. If you run into any issues with this please report them!**
+
+
 ### Pre-packaged binaries
 
 #### GitHub releases