+ display lack of map in a nice way, don't generate bogus preview in the background
* improve map selection behavior in online mode, so that players can load a missing map and have it correctly selected after pressing F5 without any rejoin, map-reselection. also doesn't cause "different maps generated" anymore if map is missing, instead the person lacking the map gets "invalid genmap" and drops out of game immediatly
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)