Deanon diff, disk, ndb, libavl, and libbio

What's left is mainly graphics. We need to deanon some Mouse and QLock structs.

Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>

sys/src/cmd/diff/diff.json

@@ -1,8 +1,5 @@
 {
 	"diff": {
-	"CFlags": [
-		"-fplan9-extensions"
-	],
 		"Include": [
 			"../cmd.json"
 		],

sys/src/cmd/disk/disk.json

@@ -1,8 +1,5 @@
 {
 	"disk": {
-		"CFlags": [
-		"-fplan9-extensions"
-		],
 		"Include": [
 			"../cmd.json"
 		],

sys/src/cmd/ndb/ndb.json

@@ -1,8 +1,5 @@
 {
 	"ndb": {
-	"CFlags": [
-		"-fplan9-extensions"
-	],
 		"Include": [
 			"/sys/src/cmd/cmd.json"
 		],

sys/src/libavl/libavl.json

@@ -1,7 +1,6 @@
 {
 	"libavl": {
 		"Cflags": [
-			"-fplan9-extensions",
 			"-Werror"
 		],
 		"Include": [

sys/src/libbio/libbio.json

@@ -1,7 +1,6 @@
 {
 	"libbio": {
 		"Cflags": [
-			"-fplan9-extensions",
 			"-Werror"
 		],
 		"Include": [