Changed when to enable custom baud by default

Be very conservative when enabling custom baudrate
support (USE_CUSTOM_BAUD) by default. Only enable (by default) on
systems where we know it will cause no problems. For other systems the
user can try to enable it explicitly (see Makefile).

Currently enabled by default on:

  Linux, Kernel verison > 2.6.0, x86 and x86_64 architectures
  FreeBSD, OpenBSD, NetBSD, DragonFly BSD

custbaud.h

@@ -30,6 +30,7 @@
 
 #if defined (__linux__)
 
+/* Enable by-default for kernels > 2.6.0 on x86 and x86_64 only */
 #include <linux/version.h>
 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0)
 #if defined (__x86__) || defined (__x86_64__) || defined (USE_CUSTOM_BAUD)
@@ -40,9 +41,20 @@
 #endif /* of arch */
 #endif /* of version */
 
-#elif defined (__FreeBSD__) || defined (__OpenBSD__) || \
-      defined (__DragonFly__) || defined (__APPLE__)
+#elif defined (__APPLE__)
 
+/* ?? Maybe enable by-default for specific versions ?? */
+#define CUSTOM_BAUD_HEAD "custbaud_bsd.h"
+
+#elif defined (__NetBSD__)
+
+/* Do not enable by default */
+#define CUSTOM_BAUD_HEAD "custbaud_bsd.h"
+
+#elif defined (__FreeBSD__) || defined (__OpenBSD__) || \
+      defined (__DragonFly__)
+
+/* I believe it doesn't hurt to enable by-default for these */
 #ifndef USE_CUSTOM_BAUD
 #define USE_CUSTOM_BAUD
 #endif

custbaud_bsd.c

@@ -42,8 +42,9 @@
 
 /* Note that this code might also work with other BSD variants, but I have only
  * tested with those listed below. Also tested __NetBSD__ but won't work. */
-#if (defined (__FreeBSD__) || defined (__OpenBSD__) || \
-     defined (__DragonFly__) || defined (__APPLE__)) && \
+#if (defined (__FreeBSD__) || defined (__NetBSD__) ||       \
+     defined (__OpenBSD__) || defined (__DragonFly__) ||    \
+     defined (__APPLE__)) &&                                \
     defined (USE_CUSTOM_BAUD)
 
 #include "custbaud_bsd.h"