Propagate unexported deps via implementation_deps

Test: bp2build and mixed_libc CI
Test: Manually verified that libc_bionic_ndk compilation gets the
appropriate headers (and no extra headers) from downstream

Change-Id: I79eb6e8ec1d415bd50d12105da4cf97101f95474
diff --git a/cc/library_headers.go b/cc/library_headers.go
index 0aba8de..2065929 100644
--- a/cc/library_headers.go
+++ b/cc/library_headers.go
@@ -109,10 +109,11 @@
 }
 
 type bazelCcLibraryHeadersAttributes struct {
-	Copts    bazel.StringListAttribute
-	Hdrs     bazel.LabelListAttribute
-	Includes bazel.StringListAttribute
-	Deps     bazel.LabelListAttribute
+	Copts               bazel.StringListAttribute
+	Hdrs                bazel.LabelListAttribute
+	Includes            bazel.StringListAttribute
+	Deps                bazel.LabelListAttribute
+	Implementation_deps bazel.LabelListAttribute
 }
 
 type bazelCcLibraryHeaders struct {
@@ -147,9 +148,10 @@
 	linkerAttrs := bp2BuildParseLinkerProps(ctx, module)
 
 	attrs := &bazelCcLibraryHeadersAttributes{
-		Copts:    compilerAttrs.copts,
-		Includes: exportedIncludes,
-		Deps:     linkerAttrs.deps,
+		Copts:               compilerAttrs.copts,
+		Includes:            exportedIncludes,
+		Implementation_deps: linkerAttrs.deps,
+		Deps:                linkerAttrs.exportedDeps,
 	}
 
 	props := bazel.BazelTargetModuleProperties{