[OE-core] [PATCH] gettext.bbclass: Ensure we don't overwrite other DEPENDS_GETTEXT values

[Richard Purdie]

In particular, this overwrites the value from cross-canadian.bbclass in
some cases which isn't the desired behaviour and unnecessarily
complicates/breaks the dependency chain.

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
---
diff --git a/meta/classes/gettext.bbclass b/meta/classes/gettext.bbclass
index 89faa30..95818c6 100644
--- a/meta/classes/gettext.bbclass
+++ b/meta/classes/gettext.bbclass
@@ -15,7 +15,7 @@ def gettext_oeconf(d):
         return '--disable-nls'
     return "--enable-nls"
 
-DEPENDS_GETTEXT = "virtual/gettext gettext-native"
+DEPENDS_GETTEXT ??= "virtual/gettext gettext-native"
 
 BASEDEPENDS =+ "${@gettext_dependencies(d)}"
 EXTRA_OECONF_append = " ${@gettext_oeconf(d)}"