Make sky, horizon, flakes and clouds optional, replace repeated strips of skyL/skyR with 2x2 transparent PNGs instead of larger images of variable dimensions, remove a number of empty unused images
FIND_PATH(GMP_INCLUDE_DIR gmp.h)
FIND_LIBRARY(GMP_LIBRARY NAMES GMP gmp)
IF (GMP_INCLUDE_DIR AND GMP_LIBRARY)
SET(GMP_FOUND TRUE)
ENDIF (GMP_INCLUDE_DIR AND GMP_LIBRARY)
IF (GMP_FOUND)
IF (NOT GMP_FIND_QUIETLY)
MESSAGE(STATUS "Found GMP: ${GMP_LIBRARY}")
ENDIF (NOT GMP_FIND_QUIETLY)
ELSE (GMP_FOUND)
IF (GMP_FIND_REQUIRED)
MESSAGE(FATAL_ERROR "Could not find GMP")
ENDIF (GMP_FIND_REQUIRED)
ENDIF (GMP_FOUND)