Revert "bp2build: convert host & prebuilt header libraries"

This reverts commit d8a72d7dc91b2122b7b10b47b80cf2f7c65f9049.

Reason for revert: root cause for b/214013899

Change-Id: If769708408c419c2fd3d9484fbf40202b7276299
diff --git a/cc/cc.go b/cc/cc.go
index 82b7c87..281ebc1 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -3476,7 +3476,9 @@
 				libraryBp2Build(ctx, c)
 			}
 		} else if !static && !shared {
-			libraryHeadersBp2Build(ctx, c)
+			if !prebuilt {
+				libraryHeadersBp2Build(ctx, c)
+			}
 		} else if static {
 			if prebuilt {
 				prebuiltLibraryStaticBp2Build(ctx, c)