make[2]: Entering directory `/crawl/crawl-ref/source/contrib/sdl2-mixer'
     * rebuilding sdl2-mixer: new build flags or prefix
     CXX external/libmodplug-0.8.8.4/src/fastmix.o
     CXX external/libmodplug-0.8.8.4/src/load_669.o
     CXX external/libmodplug-0.8.8.4/src/load_abc.o
  external/libmodplug-0.8.8.4/src/load_abc.cpp: In function 'ABCHANDLE* ABC_Init()':
  external/libmodplug-0.8.8.4/src/load_abc.cpp:2405:40: error: 'setenv' was not declared in this scope
       setenv(ABC_ENV_NORANDOMPICK, buf, 1);
                                          ^
  external/libmodplug-0.8.8.4/src/load_abc.cpp:2417:39: error: 'setenv' was not declared in this scope
      setenv(ABC_ENV_NORANDOMPICK, buf, 1);
                                         ^
  make[2]: *** [external/libmodplug-0.8.8.4/src/load_abc.o] Error 1
  make[2]: Leaving directory `/crawl/crawl-ref/source/contrib/sdl2-mixer'
  make[1]: *** [sdl2-mixer] Error 2
  make[1]: Leaving directory `/crawl/crawl-ref/source/contrib'
  make: *** [.contrib-libs] Error 2