Fix issue 182.

src/nvtt/squish/CMakeLists.txt

@@ -23,8 +23,13 @@ SET(SQUISH_SRCS
 ADD_LIBRARY(squish STATIC ${SQUISH_SRCS})
 
 IF(NOT WIN32)
-    IF(CMAKE_COMPILER_IS_GNUCXX)
-        SET_TARGET_PROPERTIES(squish PROPERTIES COMPILE_FLAGS -fPIC)
-    ENDIF(CMAKE_COMPILER_IS_GNUCXX)
+
+	IF("${CMAKE_CXX_COMPILER}" MATCHES "clang(\\+\\+)?$" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+		SET(CMAKE_COMPILER_IS_CLANGXX 1)
+	ENDIF()
+
+    IF(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_COMPILER_IS_CLANGXX)
+		SET_TARGET_PROPERTIES(squish PROPERTIES COMPILE_FLAGS -fPIC)
+    ENDIF(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_COMPILER_IS_CLANGXX)
 ENDIF(NOT WIN32)