Hunk 1: Pass -std=c99 when building with clang as well as GCC.
Hunk 2: Stop adding the doc/ directory twice, there is another entry for it
        at the end of the file.
--- CMakeLists.txt.orig	2014-11-04 18:43:47 UTC
+++ CMakeLists.txt
@@ -106,10 +106,10 @@ if(K3B_BUILD_FFMPEG_DECODER_PLUGIN)
     include(CMakePushCheckState)
     cmake_push_check_state()
 
-    if(CMAKE_COMPILER_IS_GNUCC)
+    if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_C_COMPILER_ID}" MATCHES "Clang") 
       # FindKDE4Internal.cmake screws things up
       set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS} -std=c99)
-    endif(CMAKE_COMPILER_IS_GNUCC)
+    endif(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_C_COMPILER_ID}" MATCHES "Clang") 
 
     if(FFMPEG_INCLUDE_DIR_OLD_STYLE)
       set(CMAKE_REQUIRED_INCLUDES ${CMAKE_REQUIRED_INCLUDES} ${FFMPEG_INCLUDE_DIR_OLD_STYLE})
@@ -339,7 +339,6 @@ add_subdirectory( libk3b )
 add_subdirectory( src )
 add_subdirectory( kioslaves )
 add_subdirectory( plugins )
-add_subdirectory( doc )
 if(BUILD_K3BSETUP)
    add_subdirectory(k3bsetup)
 endif(BUILD_K3BSETUP)