diff --git a/Build.md b/Build.md
index 9cd1241..8c6e4da 100644
--- a/Build.md
+++ b/Build.md
@@ -3,20 +3,33 @@ system-specific sections below if you'd like to investigate that.
 
 Otherwise, you'll need to build **ccls** from source.  You will need:
 
-* The source code for **ccls**.
 * [CMake](https://cmake.org/) 3.8 or higher.
 * A C++ compiler with C++17 support:
   * Clang 5 or higher.
   * GCC 7.2 or higher (`optional,string_view` require libstdc++7 or higher)
   * MSVC 2017 or higher (included with VS2017 Build Tools)
 * On POSIX systems, either GNU make or Ninja (optional on other systems)
+* Clang+LLVM headers and libraries
 
 The simplest/quickest build with all defaults (only for POSIX systems) is:
 
 ```sh
 git clone --depth=1 --recursive https://github.com/MaskRay/ccls
 cd ccls
-cmake -H. -BRelease -DCMAKE_BUILD_TYPE=Release
+
+# Download "Pre-Built Binaries" from https://releases.llvm.org/downloads.html
+# and unpack to /path/to/clang+llvm-xxx
+cmake -H. -BRelease -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=/path/to/clang+llvm-xxx
+cmake --build Release
+```
+
+The Ubuntu 16.04 prebuit binaries are actually suitable for many non-Ubuntu distributions.
+You may relace the last two cmake commands with:
+
+```sh
+wget -c http://releases.llvm.org/7.0.1/clang+llvm-7.0.1-x86_64-linux-gnu-ubuntu-16.04.tar.xz
+tar xf clang+llvm-7.0.1-x86_64-linux-gnu-ubuntu-16.04.tar.xz
+cmake -H. -BRelease -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=$PWD/clang+llvm-7.0.1-x86_64-linux-gnu-ubuntu-16.04
 cmake --build Release
 ```
 
@@ -82,65 +95,51 @@ for your system, as well as methods of obtaining and locating Clang+LLVM.
 
 ## Choosing Clang+LLVM
 
-**ccls** requires LLVM and Clang. There are many ways they can be obtained.
-
-* `-DSYSTEM_CLANG=(ON|OFF)`
-
-  Default: **OFF**
-
-  The default behavior of CMake is to download a pre-built binary of Clang.
-  If you prefer a different approach add `-DSYSTEM_CLANG=ON` and choose a
-  method below.
-
-### System Clang+LLVM
-
-If you want to link against a version of Clang+LLVM already installed on your
-system you will need to install `libclang-*-dev` and `llvm-*-dev` packages (or
-equivalent) in order to have the correct libraries.  If they are installed
-into the standard locations for our system, CMake will locate them.
-
-Use `-DSYSTEM_CLANG=ON`.
-
 * `-DCMAKE_PREFIX_PATH=<path>`
 
   CMake searches the paths in `CMAKE_PREFIX_PATH` for `include` and `lib`
   subdirectories containing the required Clang headers and libraries, e.g.
 
-  `-DSYSTEM_CLANG=ON -DCMAKE_PREFIX_PATH=/usr/local/llvm70`
+  If you want to link against a version of Clang+LLVM already installed on your
+  system you will need to install packages (or equivalent) in order to have the
+  correct libraries.  e.g. `-DCMAKE_PREFIX_PATH=/usr/local/llvm70`
+
+**ccls** requires LLVM and Clang. There are many ways they can be obtained.
+
+### System Clang+LLVM
+
+If they are installed into the standard locations for our system, CMake will locate them.
+
+On Debian and its derivatives, you may install `libclang-*-dev` and `llvm-*-dev`.
 
   You may add multiple directories for `include` and `lib` separated by a `;`.
 
-### Alternate Clang+LLVM
+### Prebuilt binaries
 
-If you wish to download and unpack Clang yourself rather than having CMake do
-it for you, or if you want to build Clang+LLVM from source, or if CMake can't
-find your installation of Clang+LLVM for any other reason, set the
-`CMAKE_PREFIX_PATH` CMake variable to point to the correct location:
+Pick the one on https://releases.llvm.org/downloads.html that suits your system.
+Note, the Ubuntu 16.04 prebuit binaries are actually suitable for many non-Ubuntu distributions.
 
-Similar as System Clang+LLVM, `-DSYSTEM_CLANG=ON -DCMAKE_PREFIX_PATH=clang+llvm-7.0.0-x86_64-linux-gnu-ubuntu-16.04`
+After unpacking, `-DCMAKE_PREFIX_PATH=/path/to/clang+llvm-7.0.1-x86_64-linux-gnu-ubuntu-16.04`
+
+The Windows prebuilt binaries lack C++ header files, thus they cannot be used.
 
 ## GNU/Linux
 
 * On GNU/Linux distributions with older versions of glibc (older than
-  2013-04-25), such as Red Hat EL 6.x, you may need to add the `-D__STDC_FORMAT_MACROS` option to `CMAKE_CXX_FLAGS`:
-
-  `-DCMAKE_CXX_FLAGS=-D__STDC_FORMAT_MACROS`
+  2013-04-25), such as Red Hat EL 6.x, append `-DCMAKE_CXX_FLAGS=-D__STDC_FORMAT_MACROS`
 
 ### Arch Linux
 
-To install pre-built **ccls**, use
-[aur/ccls-git](https://aur.archlinux.org/packages/ccls-git).
+Arch User Repository: [aur/ccls-git](https://aur.archlinux.org/packages/ccls-git).
 
-To build **ccls** on Arch Linux with system Clang+LLVM, you will need to add
-`-DLLVM_ENABLE_RTTI=on -DUSE_SHARED_LLVM=on`.
+To build **ccls** on Arch Linux with system clang+llvm: `cmake -H. -BRelease -DUSE_SHARED_LLVM=on -DLLVM_ENABLE_RTTI=on`
 
 `extra/clang` and `extra/llvm` provide `/usr/lib/{libclangAST.so,libLLVM*.a,libLLVM.so}`.
 `libclangAST.so` needs `libLLVM.so` and there would be a conflict if `libLLVM*.a` (instead of `libLLVM.so`) are linked. See https://bugs.archlinux.org/task/60512
 
 ### Gentoo Linux
 
-To build **ccls** on Gentoo Linux with system Clang+LLVM, you will need to add
-`-DLLVM_ENABLE_RTTI=on`.
+To build **ccls** on Gentoo Linux with system Clang+LLVM: `cmake -H. -BRelease -DLLVM_ENABLE_RTTI=on`
 
 ### Debian / Ubuntu
 
@@ -150,8 +149,7 @@ On Ubuntu 16.04 install g++-7 via [these directions](https://gist.github.com/jlb
 
 ### Void Linux
 
-To build **ccls** on Void Linux with system Clang+LLVM, you will need to add
-`-DLLVM_ENABLE_RTTI=on`.
+To build **ccls** on Void Linux with system Clang+LLVM: `cmake -H. -BRelease -DLLVM_ENABLE_RTTI=on`
 
 ### Red Hat / CentOS
 
@@ -165,10 +163,12 @@ To install **ccls** with Homebrew use https://github.com/twlz0ne/homebrew-ccls
 To build from source you need MacOS 10.12 (Sierra) or higher to get a version
 of Xcode with a sufficiently-new Clang.
 
-To build using MacPorts Clang add CMake flags `-DSYSTEM_CLANG=on
+To build using MacPorts Clang add CMake flags
+```sh
 -DCMAKE_CXX_COMPILER=clang++-mp-6.0
 -DCMAKE_PREFIX_PATH=/opt/local/libexec/llvm-6.0 -DLLVM_ENABLE_RTTI=on
 -DUSE_SHARED_LLVM=on`
+```
 
 With clang < 8, to make header completion work, use a [shell script wrapper](Install#shell-script-wrapper):
 ```sh
@@ -181,8 +181,7 @@ See https://github.com/MaskRay/ccls/issues/191#issuecomment-453809905 for detail
 ## FreeBSD
 
 * [devel/ccls](https://www.freshports.org/devel/ccls)
-* With `devel/llvm70` add CMake flags `-DSYSTEM_CLANG=on
-  -DUSE_SHARED_LLVM=on -DCMAKE_PREFIX_PATH=/usr/local/llvm70`
+* With `devel/llvm70` add CMake flags `-DUSE_SHARED_LLVM=on -DCMAKE_PREFIX_PATH=/usr/local/llvm70`
 * To use the releases.llvm.org prebuilt archive and its libc++ add CMake flag
   `-DCLANG_USE_BUNDLED_LIBC++=on`
 
@@ -207,7 +206,7 @@ ninja -C Release clangFormat clangFrontendTool clangIndex clangTooling clang
 
 # Download ccls
 cd ccls
-cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang-cl -DSYSTEM_CLANG=On -DCMAKE_PREFIX_PATH="D:/llvm/Release;D:/llvm/Release/tools/clang;D:/llvm;D:/llvm/tools/clang"
+cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang-cl -DCMAKE_PREFIX_PATH="D:/llvm/Release;D:/llvm/Release/tools/clang;D:/llvm;D:/llvm/tools/clang"
 ninja -C Release
 ```
 
@@ -217,7 +216,7 @@ For 2, one possible way is use MSYS2, in MSYS2 MinGW 64-bit shell:
 
 ```
 pacman -S mingw-w64-x86_64-clang mingw-w64-x86_64-cmake mingw-w64-x86_64-jq mingw-w64-x86_64-ninja mingw-w64-x86_64-ncurses
-cmake -H. -BRelease -G Ninja  -DSYSTEM_CLANG=ON -DCMAKE_CXX_FLAGS=-D__STDC_FORMAT_MACROS
+cmake -H. -BRelease -G Ninja -DCMAKE_CXX_FLAGS=-D__STDC_FORMAT_MACROS
 ninja -C Release
 ```
 
@@ -245,11 +244,11 @@ ninja -C Release clangFormat clangFrontendTool clangIndex clangTooling
 * Remove `LLVM_ENABLE_LLD` if you don't have lld (a much faster linker than bfd/gold) installed
 * Remove `BUILD_SHARED_LIBS` if you want to build static libraries (`libclangIndex.a`) instead
 
-Then build ccls with `-DSYSTEM_CLANG` and `-DCMAKE_PREFIX_PATH`:
+Then build ccls with `-DCMAKE_PREFIX_PATH`:
 
 ```sh
 cd ~/ccls
-cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=lld -DSYSTEM_CLANG=On -DCMAKE_PREFIX_PATH="$HOME/llvm/Release;$HOME/llvm/Release/tools/clang;$HOME/llvm;$HOME/llvm/tools/clang"
+cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=lld -DCMAKE_PREFIX_PATH="$HOME/llvm/Release;$HOME/llvm/Release/tools/clang;$HOME/llvm;$HOME/llvm/tools/clang"
 ninja -C Release
 ```