Write resolvable compatible version to the package

To avoid a clash with the regular version or an extra attribute level we
use the "package:provides.compatible" package attribute instead of
"package:version.major".

headers/private/package/hpkg/WriterImplBase.h

@@ -154,7 +154,9 @@ protected:
 									const BPackageInfo& packageInfo);
 			void				RegisterPackageVersion(
 									PackageAttributeList& attributeList,
-									const BPackageVersion& version);
+									const BPackageVersion& version,
+									BHPKGAttributeID attributeID
+										= kDefaultVersionAttributeID);
 			void				RegisterPackageResolvableExpressionList(
 									PackageAttributeList& attributeList,
 									const BObjectList<
@@ -198,6 +200,10 @@ protected:
 
 	inline	void				SetFinished(bool finished);
 
+private:
+	static const BHPKGAttributeID kDefaultVersionAttributeID
+		= B_HPKG_ATTRIBUTE_ID_PACKAGE_VERSION_MAJOR;
+
 private:
 			void				_WritePackageAttributes(
 									const PackageAttributeList& attributes);