C++: Make linking_context libraries_to_link return depset

Triggered by the flag: --incompatible_depset_for_libraries_to_link_getter

GitHub tracking issue: https://github.com/bazelbuild/bazel/issues/8118

RELNOTES:none
PiperOrigin-RevId: 245747705
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 6778ce9..5b1909f 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
@@ -200,6 +200,8 @@
 
   public abstract boolean incompatibleDoNotSplitLinkingCmdline();
 
+  public abstract boolean incompatibleDepsetForLibrariesToLinkGetter();
+
   /** Returns a {@link Builder} initialized with the values of this instance. */
   public abstract Builder toBuilder();
 
@@ -256,6 +258,7 @@
           .incompatibleStringJoinRequiresStrings(false)
           .internalSkylarkFlagTestCanary(false)
           .incompatibleDoNotSplitLinkingCmdline(false)
+          .incompatibleDepsetForLibrariesToLinkGetter(false)
           .build();
 
   /** Builder for {@link StarlarkSemantics}. All fields are mandatory. */
@@ -346,6 +349,8 @@
 
     public abstract Builder incompatibleDoNotSplitLinkingCmdline(boolean value);
 
+    public abstract Builder incompatibleDepsetForLibrariesToLinkGetter(boolean value);
+
     public abstract StarlarkSemantics build();
   }
 }