For non-embedded platforms, increase the size of the argument list.

Note that this results in more kernel virtual memory being reserved for
temporary storage of the args.  The args temporary space is allocated out
of exec_map (a submap of kernel_map).  This will use roughly 4MB of KVM.

OK'ed by:	dg

sys/sys/syslimits.h

@@ -43,7 +43,11 @@
  * Do not add any new variables here.  (See the comment at the end of
  * the file for why.)
  */
+#if defined(__arm__) || defined(__powerpc__)
 #define	ARG_MAX			65536	/* max bytes for an exec function */
+#else
+#define	ARG_MAX			262144	/* max bytes for an exec function */
+#endif
 #ifndef CHILD_MAX
 #define	CHILD_MAX		   40	/* max simultaneous processes */
 #endif