diff --git a/configure.ac b/configure.ac
index 5b155a8..12687e1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,13 +13,33 @@ if test "$libxmp_path" != ""; then
   LIBS="${LIBS} -L${libxmp_path}/lib"
 fi
 
+AC_DEFUN([AC_CHECK_DEFINED],[
+  AS_VAR_PUSHDEF([ac_var],[ac_cv_defined_$1])dnl
+  AC_CACHE_CHECK([for $1 defined], ac_var,
+  AC_TRY_COMPILE(,[
+    #ifdef $1
+    int ok;
+    #else
+    choke me
+    #endif
+  ],AS_VAR_SET(ac_var, yes),AS_VAR_SET(ac_var, no)))
+  AS_IF([test AS_VAR_GET(ac_var) != "no"], [$2], [$3])dnl
+  AS_VAR_POPDEF([ac_var])dnl
+])
+
 AC_CHECK_HEADERS(xmp.h getopt.h signal.h termios.h)
 
-AC_CHECK_HEADER(windows.h,,[
+system=unknown
+
+AC_CHECK_DEFINED(_WIN32,[system=win32])
+AC_CHECK_DEFINED(__BEOS__,[system=beos])
+AC_CHECK_DEFINED(__HAIKU__,[system=beos])
+
+if test "$system" = "unknown"; then
   AC_CHECK_HEADER(CoreAudio/CoreAudio.h,,[
     AC_CHECK_HEADERS(sys/soundcard.h alsa/asoundlib.h sndio.h sys/audioio.h)
   ])
-])
+fi
 
 if test "${ac_cv_header_xmp_h}" = "yes"; then
   AC_CHECK_LIB(xmp,xmp_player_start,,
@@ -28,38 +48,44 @@ else
   AC_MSG_ERROR(Can't find libxmp header files)
 fi
 
-if test -f /system/Tracker; then
+case "$system" in
+beos)
   AC_DEFINE(SOUND_BEOS)
   DRIVERS="${DRIVERS} sound_beos.o"
   LIBS="${LIBS} -lmedia -lbe"
-elif test "${ac_cv_header_windows_h}" = "yes"; then
+  ;;
+win32)
   AC_DEFINE(SOUND_WIN32)
   DRIVERS="${DRIVERS} sound_win32.o"
   LIBS="${LIBS} -lwinmm"
-elif test "${ac_cv_header_CoreAudio_CoreAudio_h}" = "yes"; then
-  AC_DEFINE(SOUND_COREAUDIO)
-  DRIVERS="${DRIVERS} sound_coreaudio.o"
-  LIBS="${LIBS} -framework AudioToolbox -framework AudioUnit -framework CoreServices"
-else
-  if test "${ac_cv_header_sndio_h}" = "yes"; then
-    AC_DEFINE(SOUND_SNDIO)
-    DRIVERS="${DRIVERS} sound_sndio.o"
-    LIBS="${LIBS} -lsndio"
-  fi
-  if test "${ac_cv_header_sys_audioio_h}" = "yes"; then
-    AC_DEFINE(SOUND_BSD)
-    DRIVERS="${DRIVERS} sound_bsd.o"
-  fi
-  if test "${ac_cv_header_sys_soundcard_h}" = "yes"; then
-    AC_DEFINE(SOUND_OSS)
-    DRIVERS="${DRIVERS} sound_oss.o"
-  fi
-  if test "${ac_cv_header_alsa_asoundlib_h}" = "yes"; then
-    AC_DEFINE(SOUND_ALSA)
-    DRIVERS="${DRIVERS} sound_alsa.o"
-    LIBS="${LIBS} -lasound"
+  ;;
+*)
+  if test "${ac_cv_header_CoreAudio_CoreAudio_h}" = "yes"; then
+    AC_DEFINE(SOUND_COREAUDIO)
+    DRIVERS="${DRIVERS} sound_coreaudio.o"
+    LIBS="${LIBS} -framework AudioToolbox -framework AudioUnit -framework CoreServices"
+  else
+    if test "${ac_cv_header_sndio_h}" = "yes"; then
+      AC_DEFINE(SOUND_SNDIO)
+      DRIVERS="${DRIVERS} sound_sndio.o"
+      LIBS="${LIBS} -lsndio"
+    fi
+    if test "${ac_cv_header_sys_audioio_h}" = "yes"; then
+      AC_DEFINE(SOUND_BSD)
+      DRIVERS="${DRIVERS} sound_bsd.o"
+    fi
+    if test "${ac_cv_header_sys_soundcard_h}" = "yes"; then
+      AC_DEFINE(SOUND_OSS)
+      DRIVERS="${DRIVERS} sound_oss.o"
+    fi
+    if test "${ac_cv_header_alsa_asoundlib_h}" = "yes"; then
+      AC_DEFINE(SOUND_ALSA)
+      DRIVERS="${DRIVERS} sound_alsa.o"
+      LIBS="${LIBS} -lasound"
+    fi
   fi
-fi
+  ;;
+esac
 
 dnl XMP_TRY_COMPILE(<message>,<cache-var>,<flags>,<program>,<ifyes>,<ifno>)
 define(XMP_TRY_COMPILE,[