Update makefiles.

Note cleanspec required because of b/38205169 (genrule
doesn't delete output files before building, so when
removing some, they get stale).

Test: power vts test compiles
Change-Id: Ie7ef0fc3d943a75fe898238cf861fb7f99f4146b
Fixes: 35813011
diff --git a/wifi/offload/1.0/Android.bp b/wifi/offload/1.0/Android.bp
index 7b1b050..63f85a6 100644
--- a/wifi/offload/1.0/Android.bp
+++ b/wifi/offload/1.0/Android.bp
@@ -12,7 +12,7 @@
 genrule {
     name: "android.hardware.wifi.offload@1.0_genc++",
     tools: ["hidl-gen"],
-    cmd: "$(location hidl-gen) -o $(genDir) -Lc++ -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport android.hardware.wifi.offload@1.0",
+    cmd: "$(location hidl-gen) -o $(genDir) -Lc++-sources -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport android.hardware.wifi.offload@1.0",
     srcs: [
         ":android.hardware.wifi.offload@1.0_hal",
     ],
@@ -26,7 +26,7 @@
 genrule {
     name: "android.hardware.wifi.offload@1.0_genc++_headers",
     tools: ["hidl-gen"],
-    cmd: "$(location hidl-gen) -o $(genDir) -Lc++ -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport android.hardware.wifi.offload@1.0",
+    cmd: "$(location hidl-gen) -o $(genDir) -Lc++-headers -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport android.hardware.wifi.offload@1.0",
     srcs: [
         ":android.hardware.wifi.offload@1.0_hal",
     ],