cmake defaults stage1 to install in build directory

Author: andrewrk

CMakeLists.txt

@@ -5,6 +5,11 @@ if(NOT CMAKE_BUILD_TYPE)
         "Choose the type of build, options are: Debug Release RelWithDebInfo MinSizeRel." FORCE)
 endif()
 
+if(NOT CMAKE_INSTALL_PREFIX)
+  set(CMAKE_INSTALL_PREFIX "${CMAKE_BINARY_DIR}" CACHE STRING
+      "Directory to install zig to" FORCE)
+endif()
+
 project(zig C CXX)
 set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
 

README.md

@@ -141,10 +141,10 @@ libc. Create demo games using Zig.
 ```
 mkdir build
 cd build
-cmake .. -DCMAKE_INSTALL_PREFIX=$(pwd)
+cmake ..
 make
 make install
-./zig build --build-file ../build.zig test
+bin/zig build --build-file ../build.zig test
 ```
 
 ##### MacOS
@@ -154,9 +154,9 @@ brew install cmake llvm@6
 brew outdated llvm@6 || brew upgrade llvm@6
 mkdir build
 cd build
-cmake .. -DCMAKE_PREFIX_PATH=/usr/local/opt/llvm@6/ -DCMAKE_INSTALL_PREFIX=$(pwd)
+cmake .. -DCMAKE_PREFIX_PATH=/usr/local/opt/llvm@6/
 make install
-./zig build --build-file ../build.zig test
+bin/zig build --build-file ../build.zig test
 ```
 
 ##### Windows