Add a section for clang to doc/make/ccache.md

doc/make/ccache.md

@@ -1,5 +1,5 @@
 Using ccache
-------------
+============
 
 [ccache](http://ccache.samba.org/manual.html) is available in many
 systems, and can dramatically improve compilation times. In particular
@@ -9,6 +9,9 @@ On Ubuntu, we can install ccache by executing
 
     sudo apt-get install ccache
 
+Using ccache with g++
+---------------------
+
 Then, we can create a simple script that invokes ccache with our
 favorite C++ 11 compiler. For example, we can create the script
 `~/bin/ccache-g++` with the following content:
@@ -24,3 +27,17 @@ We usually use Ninja instead of make. Thus, our cmake command
 line is:
 
     cmake -D CMAKE_BUILD_TYPE=Debug -D CMAKE_CXX_COMPILER=~/bin/ccache-g++ -G Ninja ../../src
+
+Using ccache with clang++
+-------------------------
+
+To use ccache with clang++, create the script ``~/bin/ccache-clang++``
+with the following content:
+
+    #!/bin/sh
+    ccache clang++ -Qunused-arguments -fcolor-diagnostics "$@"
+
+ - ``-Qunused-arguments`` option is used to supprress "clang: warning:
+   argument unused during compilation:" warning.
+ - ``-fcolor-diagnostics`` option is used to enable clang's colored
+   diagnostic messages.