Remove library decorator for extracting headers

It is unused and removing it allows us to use the same function for
prebuilt/not libraries.

Test: bp2build.sh
Change-Id: I92ac56496cff2c2e55d6eb9f261fe75a1b232856
diff --git a/cc/library.go b/cc/library.go
index fdbbccb..8f8e038 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -289,7 +289,7 @@
 	baseAttributes := bp2BuildParseBaseProps(ctx, m)
 	compilerAttrs := baseAttributes.compilerAttributes
 	linkerAttrs := baseAttributes.linkerAttributes
-	exportedIncludes := bp2BuildParseExportedIncludes(ctx, m, compilerAttrs.includes)
+	exportedIncludes := bp2BuildParseExportedIncludes(ctx, m, &compilerAttrs.includes)
 
 	srcs := compilerAttrs.srcs
 
@@ -2450,7 +2450,7 @@
 	compilerAttrs := baseAttributes.compilerAttributes
 	linkerAttrs := baseAttributes.linkerAttributes
 
-	exportedIncludes := bp2BuildParseExportedIncludes(ctx, module, compilerAttrs.includes)
+	exportedIncludes := bp2BuildParseExportedIncludes(ctx, module, &compilerAttrs.includes)
 
 	// Append shared/static{} stanza properties. These won't be specified on
 	// cc_library_* itself, but may be specified in cc_defaults that this module