diff --git a/CMakeLists.txt b/CMakeLists.txt
index c7dc27f..74ec2a3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -173,7 +173,7 @@
   add_dependencies(jpeg-static simd)
 endif()
 
-set(TURBOJPEG_SOURCES turbojpegl.c)
+set(TURBOJPEG_SOURCES turbojpegl.c transupp.c)
 if(WITH_JNI)
   set(TURBOJPEG_SOURCES ${TURBOJPEG_SOURCES} turbojpeg-jni.c)
 endif()
@@ -187,7 +187,7 @@
 set_target_properties(turbojpeg PROPERTIES LINK_INTERFACE_LIBRARIES "")
 
 add_library(turbojpeg-static STATIC ${JPEG_SOURCES} ${SIMD_OBJS}
-  turbojpegl.c)
+  turbojpegl.c transupp.c)
 if(NOT MSVC)
   set_target_properties(turbojpeg-static PROPERTIES OUTPUT_NAME turbojpeg)
 endif()
@@ -246,6 +246,8 @@
 else()
 add_test(cjpeg-float-cmp ${CMAKE_COMMAND} -E compare_files ${CMAKE_SOURCE_DIR}/testimgflt-nosimd.jpg testoutflt.jpg)
 endif()
+add_test(cjpeg-int-gray sharedlib/cjpeg -dct int -grayscale -outfile testoutgray.jpg ${CMAKE_SOURCE_DIR}/testorig.ppm)
+add_test(cjpeg-int-gray-cmp ${CMAKE_COMMAND} -E compare_files ${CMAKE_SOURCE_DIR}/testimggray.jpg testoutgray.jpg)
 add_test(djpeg-int sharedlib/djpeg -dct int -fast -ppm -outfile testoutint.ppm ${CMAKE_SOURCE_DIR}/testorig.jpg)
 add_test(djpeg-int-cmp ${CMAKE_COMMAND} -E compare_files ${CMAKE_SOURCE_DIR}/testimgint.ppm testoutint.ppm)
 add_test(djpeg-fast sharedlib/djpeg -dct fast -ppm -outfile testoutfst.ppm ${CMAKE_SOURCE_DIR}/testorig.jpg)
@@ -291,6 +293,8 @@
 else()
 add_test(cjpeg-static-float-cmp ${CMAKE_COMMAND} -E compare_files ${CMAKE_SOURCE_DIR}/testimgflt-nosimd.jpg testoutflt.jpg)
 endif()
+add_test(cjpeg-static-int-gray cjpeg-static -dct int -grayscale -outfile testoutgray.jpg ${CMAKE_SOURCE_DIR}/testorig.ppm)
+add_test(cjpeg-static-int-gray-cmp ${CMAKE_COMMAND} -E compare_files ${CMAKE_SOURCE_DIR}/testimggray.jpg testoutgray.jpg)
 add_test(djpeg-static-int djpeg-static -dct int -fast -ppm -outfile testoutint.ppm ${CMAKE_SOURCE_DIR}/testorig.jpg)
 add_test(djpeg-static-int-cmp ${CMAKE_COMMAND} -E compare_files ${CMAKE_SOURCE_DIR}/testimgint.ppm testoutint.ppm)
 add_test(djpeg-static-fast djpeg-static -dct fast -ppm -outfile testoutfst.ppm ${CMAKE_SOURCE_DIR}/testorig.jpg)