find_package(JPEG REQUIRED)
# Warn if it doesn't seem to be the accelerated libjpeg that's found
+set(CMAKE_REQUIRED_LIBRARIES_OLD ${CMAKE_REQUIRED_LIBRARIES})
+set(CMAKE_REQUIRED_FLAGS_OLD ${CMAKE_REQUIRED_FLAGS})
+set(CMAKE_REQUIRED_LIBRARIES ${JPEG_LIBRARIES})
+set(CMAKE_REQUIRED_FLAGS -I${JPEG_INCLUDE_DIR})
check_c_source_compiles("#include <stdio.h>\n#include <jpeglib.h>\nint main(int c, char** v) { return JCS_EXT_RGBX; }" FOUND_JPEG_TURBO)
+set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES_OLD})
+set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS_OLD})
if(NOT FOUND_JPEG_TURBO)
message(STATUS "WARNING: You are not using libjpeg-turbo. Performance will suffer.")
endif()