diff --git a/package/pkg-generic.mk b/package/pkg-generic.mk
index 621fb91424..c46c742352 100644
--- a/package/pkg-generic.mk
+++ b/package/pkg-generic.mk
@@ -518,7 +518,7 @@ ifndef $(2)_SOURCE
  ifdef $(3)_SOURCE
   $(2)_SOURCE = $$($(3)_SOURCE)
  else ifdef $(2)_VERSION
-  $(2)_SOURCE			?= $$($(2)_BASENAME_RAW).tar.gz
+  $(2)_SOURCE			?= $$($(2)_BASENAME_RAW)$$(call pkg_source_ext,$(2))
  endif
 endif
 
diff --git a/package/pkg-utils.mk b/package/pkg-utils.mk
index a2cc160d0b..c7597a3a45 100644
--- a/package/pkg-utils.mk
+++ b/package/pkg-utils.mk
@@ -40,6 +40,11 @@ KCONFIG_DISABLE_OPT = $(call KCONFIG_MUNGE_DOT_CONFIG, $(1), $(SHARP_SIGN) $(1)
 pkgdir = $(dir $(lastword $(MAKEFILE_LIST)))
 pkgname = $(lastword $(subst /, ,$(pkgdir)))
 
+# Helper to build the extension for a package archive, based on various
+# conditions.
+# $(1): upper-case package name
+pkg_source_ext = .tar.gz
+
 # Define extractors for different archive suffixes
 INFLATE.bz2  = $(BZCAT)
 INFLATE.gz   = $(ZCAT)