gettext: Switch to disabling nls and reducing -native build dependencies to a set of pre built m4 macros

When analysing our build performance, its apparent that binutils-cross
takes an age to get built. This is due to its dependencies on
flex-native and bison-native which in turn depend on gettext-native.

gettext-native is problematic as it has a significant dependency chain
of its own and takes an age to build. What is worse is that we never
care about the native language support in -native and -cross packages
since we always force the C locale.

This patch therefore disables nls for all -native packages (its already
disabled for -cross) and adds a new gettext-minimal-native package which
contains the m4 macros to keep autoconf/automake happy.

This means we gain a significant build time speedup by the removal of
gettext-native from most dependency chains (only being part of gettext
for the target now).

For now the LICENCE field says GPLv3, the macros are actually under a
FSF MIT like licence so we need to update this part of the patch in due
course.

(From OE-Core rev: 01b2a16beb4a924077b74943ad4d6e7976563ff1)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/bison/bison_2.5.bb

@@ -21,7 +21,7 @@ SRC_URI = "${BASE_SRC_URI} \
 SRC_URI[md5sum] = "687e1dcd29452789d34eaeea4c25abe4"
 SRC_URI[sha256sum] = "722def46e4a19a5b7a579ef30db1965f86c37c1a20a5f0113743a2e4399f7c99"
 
-DEPENDS_virtclass-native = "gettext-native"
+DEPENDS_virtclass-native = "gettext-minimal-native"
 SRC_URI_virtclass-native = "${BASE_SRC_URI}"
 
 inherit autotools gettext