diff --git a/GNUmakef.def b/GNUmakef.def
index 570e0a7..feb3029 100644
--- a/GNUmakef.def
+++ b/GNUmakef.def
@@ -45,6 +45,18 @@ EXEEXT=.exe
 OBJEXT=.o
 LIBEXT=.a
 else
+ifeq ($(OSTYPE),beos) # BeOS build
+CAT=cat
+CC=gcc
+CXX=g++
+AR=ar
+RANLIB=ranlib
+PLATFORM=be
+EXEEXT=
+OBJEXT=.o
+LIBEXT=.a
+LNKFLAGS+=-lbe
+else
 CAT=cat
 CC=gcc
 CXX=g++
@@ -57,6 +69,7 @@ LIBEXT=.a
 endif
 endif
 endif
+endif
 CFLAGS+=-g -funsigned-char $(INCS) -Wall -Wno-sign-compare -pedantic -O2 -DPRAGMA_PACK # -fomit-frame-pointer
 LNKFLAGS+=-g
 CPPFLAGS+=$(CFLAGS) -fno-exceptions -fno-rtti