Add lz4 detection for CMake configuration.

CMakeLists.txt

@@ -466,6 +466,33 @@ IF(LZO2_FOUND)
 ENDIF(LZO2_FOUND)
 MARK_AS_ADVANCED(CLEAR LZO2_INCLUDE_DIR)
 MARK_AS_ADVANCED(CLEAR LZO2_LIBRARY)
+#
+# Find LZ4
+#
+IF (LZ4_INCLUDE_DIR)
+  # Already in cache, be silent
+  SET(LZ4_FIND_QUIETLY TRUE)
+ENDIF (LZ4_INCLUDE_DIR)
+
+FIND_PATH(LZ4_INCLUDE_DIR lz4.h)
+FIND_LIBRARY(LZ4_LIBRARY NAMES lz4 liblz4)
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(LZ4 DEFAULT_MSG LZ4_LIBRARY LZ4_INCLUDE_DIR)
+IF(LZ4_FOUND)
+  SET(HAVE_LIBLZ4 1)
+  SET(HAVE_LZ4_H 1)
+  CMAKE_PUSH_CHECK_STATE()	# Save the state of the variables
+  SET(CMAKE_REQUIRED_INCLUDES ${LZ4_INCLUDE_DIR})
+  CHECK_INCLUDE_FILES("lz4hc.h" HAVE_LZ4HC_H)
+  CMAKE_POP_CHECK_STATE()	# Restore the state of the variables
+  INCLUDE_DIRECTORIES(${LZ4_INCLUDE_DIR})
+  LIST(APPEND ADDITIONAL_LIBS ${LZ4_LIBRARY})
+  #
+  # TODO: test for static library.
+  #
+ENDIF(LZ4_FOUND)
+MARK_AS_ADVANCED(CLEAR LZ4_INCLUDE_DIR)
+MARK_AS_ADVANCED(CLEAR LZ4_LIBRARY)
 
 #
 # Check headers

build/cmake/config.h.in

@@ -585,6 +585,9 @@ typedef uint64_t uintmax_t;
 /* Define to 1 if you have the `gcc' library (-lgcc). */
 #cmakedefine HAVE_LIBGCC 1
 
+/* Define to 1 if you have the `lz4' library (-llz4). */
+#cmakedefine HAVE_LIBLZ4 1
+
 /* Define to 1 if you have the `lzma' library (-llzma). */
 #cmakedefine HAVE_LIBLZMA 1
 
@@ -676,6 +679,12 @@ typedef uint64_t uintmax_t;
 /* Define to 1 if you have the `lutimes' function. */
 #cmakedefine HAVE_LUTIMES 1
 
+/* Define to 1 if you have the <lz4hc.h> header file. */
+#cmakedefine HAVE_LZ4HC_H 1
+
+/* Define to 1 if you have the <lz4.h> header file. */
+#cmakedefine HAVE_LZ4_H 1
+
 /* Define to 1 if you have the <lzmadec.h> header file. */
 #cmakedefine HAVE_LZMADEC_H 1