commit aa71f071d1de8aace1427aa26bf28f78fe8955c8
author Tom Finegan <tomfinegan@google.com> Wed Jan 31 06:54:01 2018 -0800
committer Tom Finegan <tomfinegan@google.com> Wed Jan 31 19:31:54 2018 +0000
tree 8dfb5f0bb0015986a44ca7005f7bb45570217d01
parent 5d7c1fcc32a54a5e8cc6ca94444a22b91dce4b54

Add information about extra CMake build flags to README.md

BUG=aomedia:1296

Change-Id: If9f944b58f23cdb71f919bd391f6b37e27b271f1

README.md

diff --git a/README.md b/README.md
index 7e51086..e91f10d 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@
     - [MSVC builds](#microsoft-visual-studio-builds)
     - [Xcode builds](#xcode-builds)
     - [Emscripten builds](#emscripten-builds)
+    - [Extra Build Flags](#extra-build-flags)
 2. [Testing the library](#testing-the-av1-codec)
     - [Basics](#testing-basics)
         - [Unit tests](#1_unit-tests)
@@ -267,6 +268,24 @@
     $ path/to/AOMAnalyzer path/to/examples/inspect.js path/to/av1/input/file
 ~~~
 
+### Extra build flags
+
+Three variables allow for passing of additional flags to the build system.
+
+- AOM\_EXTRA\_C\_FLAGS
+- AOM\_EXTRA\_CXX\_FLAGS
+- AOM\_EXTRA\_EXE\_LINKER\_FLAGS
+
+The build system attempts to ensure the flags passed through the above variables
+are passed to tools last in order to allow for override of default behavior.
+These flags can be used, for example, to enable asserts in a release build:
+
+~~~
+    $ cmake path/to/aom \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DAOM_EXTRA_C_FLAGS=-UNDEBUG \
+        -DAOM_EXTRA_CXX_FLAGS=-UNDEBUG
+~~~
 
 ## Testing the AV1 codec