Separate build instructions from README

README included build instructions, which made it complicated to follow.
Move the build instructions to a separate file (BUILD.md).

BUILD.md

@@ -0,0 +1,236 @@
+# Build scrcpy
+
+Here are the instructions to build _scrcpy_ (client and server).
+
+You may want to build only the client: the server binary, which will be pushed
+to the Android device, does not depend on your system and architecture. In that
+case, use the [prebuilt server] (so you will not need Java or the Android SDK).
+
+[prebuilt server]: #prebuilt-server
+
+
+## Requirements
+
+You need [adb]. It is available in the [Android SDK platform
+tools][platform-tools], or packaged in your distribution (`android-adb-tools`).
+
+On Windows, download the [platform-tools][platform-tools-windows] and extract
+the following files to a directory accessible from your `PATH`:
+ - `adb.exe`
+ - `AdbWinApi.dll`
+ - `AdbWinUsbApi.dll`
+
+The client requires [FFmpeg] and [LibSDL2]. Just follow the instructions.
+
+[adb]: https://developer.android.com/studio/command-line/adb.html
+[platform-tools]: https://developer.android.com/studio/releases/platform-tools.html
+[platform-tools-windows]: https://dl.google.com/android/repository/platform-tools-latest-windows.zip
+[ffmpeg]: https://en.wikipedia.org/wiki/FFmpeg
+[LibSDL2]: https://en.wikipedia.org/wiki/Simple_DirectMedia_Layer
+
+
+
+## System-specific steps
+
+### Linux
+
+Install the required packages from your package manager.
+
+#### Debian/Ubuntu
+
+```bash
+# runtime dependencies
+sudo apt install ffmpeg libsdl2-2.0.0
+
+# client build dependencies
+sudo apt install make gcc pkg-config meson \
+                 libavcodec-dev libavformat-dev libavutil-dev \
+                 libsdl2-dev
+
+# server build dependencies
+sudo apt install openjdk-8-jdk
+```
+
+#### Fedora
+
+```bash
+# enable RPM fusion free
+sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm
+
+# client build dependencies
+sudo dnf install SDL2-devel ffms2-devel meson gcc make
+
+# server build dependencies
+sudo dnf install java
+```
+
+
+
+### Windows
+
+#### Cross-compile from Linux
+
+This is the preferred method (and the way the release is built).
+
+From _Debian_, install _mingw_:
+
+```bash
+sudo apt install mingw-w64 mingw-w64-tools
+```
+
+You also need the JDK to build the server:
+
+```bash
+sudo apt install openjdk-8-jdk
+```
+
+Then generate the releases:
+
+```bash
+make -f Makefile.CrossWindows
+```
+
+It will generate win32 and win64 releases into `dist/`.
+
+
+#### In MSYS2
+
+From Windows, you need [MSYS2] to build the project. From an MSYS2 terminal,
+install the required packages:
+
+[MSYS2]: http://www.msys2.org/
+
+```bash
+# runtime dependencies
+pacman -S mingw-w64-x86_64-SDL2 \
+          mingw-w64-x86_64-ffmpeg
+
+# client build dependencies
+pacman -S mingw-w64-x86_64-make \
+          mingw-w64-x86_64-gcc \
+          mingw-w64-x86_64-pkg-config \
+          mingw-w64-x86_64-meson
+```
+
+For a 32 bits version, replace `x86_64` by `i686`:
+
+```bash
+# runtime dependencies
+pacman -S mingw-w64-i686-SDL2 \
+          mingw-w64-i686-ffmpeg
+
+# client build dependencies
+pacman -S mingw-w64-i686-make \
+          mingw-w64-i686-gcc \
+          mingw-w64-i686-pkg-config \
+          mingw-w64-i686-meson
+```
+
+Java (>= 7) is not available in MSYS2, so if you plan to build the server,
+install it manually and make it available from the `PATH`:
+
+```bash
+export PATH="$JAVA_HOME/bin:$PATH"
+```
+
+### Mac OS
+
+Install the packages with [Homebrew]:
+
+[Homebrew]: https://brew.sh/
+
+```bash
+# runtime dependencies
+brew install sdl2 ffmpeg
+
+# client build dependencies
+brew install pkg-config meson
+```
+
+Additionally, if you want to build the server, install Java 8 from Caskroom, and
+make it avaliable from the `PATH`:
+
+```bash
+brew tap caskroom/versions
+brew cask install java8
+export JAVA_HOME="$(/usr/libexec/java_home --version 1.8)"
+export PATH="$JAVA_HOME/bin:$PATH"
+```
+
+### Docker
+
+See [pierlon/scrcpy-docker](https://github.com/pierlon/scrcpy-docker).
+
+
+## Common steps
+
+If you want to build the server, install the [Android SDK] (_Android Studio_),
+and set `ANDROID_HOME` to its directory. For example:
+
+[Android SDK]: https://developer.android.com/studio/index.html
+
+```bash
+export ANDROID_HOME=~/android/sdk
+```
+
+If you don't want to build the server, use the [prebuilt server].
+
+Clone the project:
+
+```bash
+git clone https://github.com/Genymobile/scrcpy
+cd scrcpy
+```
+
+Then, build:
+
+```bash
+meson x --buildtype release --strip -Db_lto=true
+cd x
+ninja
+```
+
+### Run
+
+To run without installing:
+
+```bash
+./run x [options]
+```
+
+
+### Install
+
+After a successful build, you can install _scrcpy_ on the system:
+
+```bash
+sudo ninja install    # without sudo on Windows
+```
+
+This installs two files:
+
+ - `/usr/local/bin/scrcpy`
+ - `/usr/local/share/scrcpy/scrcpy-server.jar`
+
+Just remove them to "uninstall" the application.
+
+You can then [run](README.md#run) _scrcpy_.
+
+
+## Prebuilt server
+
+ - [`scrcpy-server-v1.3.jar`][direct-scrcpy-server].  
+   _(SHA-256: 0f9a5a217f33f0ed7a1498ceb3c0cccf31c53533893aa952e674c1571d2740c1)_
+
+[direct-scrcpy-server]: https://github.com/Genymobile/scrcpy/releases/download/v1.3/scrcpy-server-v1.3.jar
+
+Download the prebuilt server somewhere, and specify its path during the Meson
+configuration:
+
+```bash
+meson x --buildtype release --strip -Db_lto=true \
+    -Dprebuilt_server=/path/to/scrcpy-server.jar
+cd x
+ninja
+sudo ninja install
+```