diff --git a/Installation/include/CGAL/config.h b/Installation/include/CGAL/config.h
index 4654728fa22..f59a4ee9d2c 100644
--- a/Installation/include/CGAL/config.h
+++ b/Installation/include/CGAL/config.h
@@ -362,7 +362,15 @@
 #  elif BOOST_ENDIAN_LITTLE_BYTE
 #    define CGAL_LITTLE_ENDIAN
 #  else
-#    error Unknown endianness
+#    ifdef CGAL_DEFAULT_ENDIAN
+#      if CGAL_DEFAULT_ENDIAN == 0
+#        define CGAL_LITTLE_ENDIAN
+#      else
+#        define CGAL_BIG_ENDIAN
+#      endif
+#    else
+#      error Unknown endianness: Define CGAL_DEFAULT_ENDIAN to 0 for little endian and to 1 for big endian.
+#    endif
 #  endif
 #elif defined (__GLIBC__)
 #  include <endian.h>
@@ -371,7 +379,15 @@
 #  elif (__BYTE_ORDER == __BIG_ENDIAN)
 #    define CGAL_BIG_ENDIAN
 #  else
-#    error Unknown endianness
+#    ifdef CGAL_DEFAULT_ENDIAN
+#      if CGAL_DEFAULT_ENDIAN == 0
+#        define CGAL_LITTLE_ENDIAN
+#      else
+#        define CGAL_BIG_ENDIAN
+#      endif
+#    else
+#      error Unknown endianness: Define CGAL_DEFAULT_ENDIAN to 0 for little endian and to 1 for big endian.
+#    endif
 #  endif
 #elif defined(__sparc) || defined(__sparc__) \
    || defined(_POWER) || defined(__powerpc__) \
@@ -386,7 +402,15 @@
    || defined(_M_ALPHA) || defined(_WIN64)
 #  define CGAL_LITTLE_ENDIAN
 #else
-#  error Unknown endianness
+#  ifdef CGAL_DEFAULT_ENDIAN
+#    if CGAL_DEFAULT_ENDIAN == 0
+#      define CGAL_LITTLE_ENDIAN
+#    else
+#      define CGAL_BIG_ENDIAN
+#    endif
+#  else
+#    error Unknown endianness: Define CGAL_DEFAULT_ENDIAN to 0 for little endian and to 1 for big endian.
+#  endif
 #endif
 
 
@@ -550,7 +574,7 @@ using std::max;
 #  define CGAL_NORETURN  __attribute__ ((__noreturn__))
 #elif defined (_MSC_VER)
 #  define CGAL_NORETURN __declspec(noreturn)
-#else  
+#else
 #  define CGAL_NORETURN
 #endif