added clang support to readme

README.md

@@ -76,6 +76,7 @@ code) to be usable on a wide range of target systems. It has been tested on
 the following OS/compiler/architecture combinations:
 
   - Linux (Ubuntu 12.10) / GCC 4.8.1 / x86, x86_64
+  - Linux (Ubuntu 12.04) / Clang 3.0.0 / x86_64
   - Linux (Ubuntu 14.04) / GCC 4.8.2 / ARMv7
   - Windows
     * MSVC 12.0.21005.1 REL / x86, x86_64
@@ -135,7 +136,7 @@ assumed that the project's root directory is now the parent directory.
 
 Choose an appropriate build file generator for your system.
 
-  - For Linux, GCC, x86/x86_64/ARM:       "Unix Makefiles"
+  - For Linux, GCC/Clang, x86/x86_64/ARM: "Unix Makefiles"
   - For Windows, MSVC of VS 2013, x86:    "Visual Studio 12"
   - For Windows, MSVC of VS 2013, x86_64: "Visual Studio 12 Win64"
   - For Windows, MSVC of VS 2012, x86:    "Visual Studio 11"
@@ -152,6 +153,11 @@ option -DCMAKE_BUILD_TYPE=[Release|Debug]. If no build mode is given on Linux,
 the default (Release) is used. The Visual Studio generators create build files
 for both modes (the selection is done at build time).
 
+You may choose a custom compiler instead the default one by defining
+CMAKE_CXX_COMPILER and/or CMAKE_C_COMPILER. E.g. to use clang on Linux use:
+
+    cmake .. -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_C_COMPILER=clang
+
 EMB² can be built with and without C++ exception handling, which has to be
 specified on build file generation. When exceptions are turned off, an error
 message is emitted and the program aborts in case of an exception within EMB².