Add --incompatible_disable_third_party_license_checking.

This flag makes all license-related BUILD syntax no-ops.

After this flag is permanently turned on in Bazel, we can start
stripping out the syntax.

This is unfortunately complex because it has to coherently interplay
with the related flag --check_third_party_targets_have_licenses.

See #7444 and #7553.

PiperOrigin-RevId: 235779781
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java b/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
index 775289e..b66b6ac 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
@@ -139,6 +139,8 @@
 
   public abstract boolean incompatibleDepsetUnion();
 
+  public abstract boolean incompatibleDisableThirdPartyLicenseChecking();
+
   public abstract boolean incompatibleDisableDeprecatedAttrParams();
 
   public abstract boolean incompatibleDisableObjcProviderResources();
@@ -215,6 +217,7 @@
           .incompatibleBzlDisallowLoadAfterStatement(false)
           .incompatibleDepsetIsNotIterable(false)
           .incompatibleDepsetUnion(false)
+          .incompatibleDisableThirdPartyLicenseChecking(false)
           .incompatibleDisableDeprecatedAttrParams(false)
           .incompatibleDisableObjcProviderResources(false)
           .incompatibleDisallowDataTransition(true)
@@ -269,6 +272,8 @@
 
     public abstract Builder incompatibleDepsetUnion(boolean value);
 
+    public abstract Builder incompatibleDisableThirdPartyLicenseChecking(boolean value);
+
     public abstract Builder incompatibleDisableDeprecatedAttrParams(boolean value);
 
     public abstract Builder incompatibleRequireFeatureConfigurationForPic(boolean value);