Hide vfs.pfs.trace variable if it is not used.

sys/fs/pseudofs/pseudofs.c

@@ -52,9 +52,11 @@ static MALLOC_DEFINE(M_PFSNODES, "pfs_nodes", "pseudofs nodes");
 SYSCTL_NODE(_vfs, OID_AUTO, pfs, CTLFLAG_RW, 0,
     "pseudofs");
 
+#ifdef PSEUDOFS_TRACE
 int pfs_trace;
 SYSCTL_INT(_vfs_pfs, OID_AUTO, trace, CTLFLAG_RW, &pfs_trace, 0,
     "enable tracing of pseudofs vnode operations");
+#endif
 
 #if PFS_FSNAMELEN != MFSNAMELEN
 #error "PFS_FSNAMELEN is not equal to MFSNAMELEN"

sys/modules/pseudofs/Makefile

@@ -23,4 +23,10 @@ EXPORT_SYMS=	pfs_mount	\
 		pfs_enable	\
 		pfs_destroy
 
+.if !defined(KERNBUILDDIR)
+.if defined(PSEUDOFS_TRACE)
+CFLAGS+=-DPSEUDOFS_TRACE
+.endif
+.endif
+
 .include <bsd.kmod.mk>