[patches] RFC: Locale option group

[Jim Blandy <jimb@xxxxxxxxxxxxxxxx>]

Here's a patch to create a new option group, OPTION_EGLIBC_LOCALES,
containing EGLIBC's locale data files.  Disabling this option group
reduces the size of an ARM eglibc installation by about 90%, from
262MiB to 25MiB (for one multilib).

One thing I suspect is wrong off the bat: the locale source files,
installed compressed under $sysroot/usr/share/i18n/locales, probably
ought to also be placed in the OPTION_EGLIBC_LOCALES option group too
(except for the POSIX locale, which is always present).  I don't see
any use for installing sources for locales the system doesn't
support.  I think doing so would reduce the increase the savings to
around 92% (20MiB per multilib).

Should the character maps in localedata/charmaps also be in this
option group?  Alternatively, I'd been planning on creating an option
group for the gconv character set conversion libraries, installed in
/usr/lib/gconv; should the character maps be grouped with those
instead?

And there may be other ways to better reflect the logical structure of
the locale data in the option groups; suggestions are welcome.

The patch is in two parts, one for libc and one for localedef.

ChangeLog.eglibc:
2006-12-26  Jim Blandy  <jimb@xxxxxxxxxxxxxxxx>

       * option-groups.def, option-groups.defaults (OPTION_EGLIBC_LOCALES):
       New option group.
       * localedata/Makefile: Trim locale list if
       OPTION_EGLIBC_LOCALES is not enabled.

Index: option-groups.def
===================================================================
--- option-groups.def	(revision 158625)
+++ option-groups.def	(working copy)
@@ -42,3 +42,10 @@
    help
        This option group includes functions for accessing message
        catalogs: catopen, catclose, and catgets.
+
+config OPTION_EGLIBC_LOCALES
+   bool "Locale definitions"
+   help
+       This option group includes all locale definitions other than
+       that for the "C" locale.  If this option group is omitted, then
+       only the "C" locale is supported.
Index: localedata/Makefile
===================================================================
--- localedata/Makefile	(revision 158625)
+++ localedata/Makefile	(working copy)
@@ -22,6 +22,8 @@
 
 all: # Make this the default target; it will be defined in Rules.
 
+include ../option-groups.mak
+
 # List with all available character set descriptions.
 charmaps := $(filter-out $(addprefix charmaps/, CVS RCS SCCS %~), \
 				     $(wildcard charmaps/[A-I]*) \
@@ -203,6 +205,11 @@
 
 include SUPPORTED
 
+# Only install locale data if OPTION_EGLIBC_LOCALES is selected.
+ifneq ($(OPTION_EGLIBC_LOCALES),y)
+SUPPORTED-LOCALES :=
+endif
+
 INSTALL-SUPPORTED-LOCALES=$(addprefix install-, $(SUPPORTED-LOCALES))
 
 # Sometimes the whole collection of locale files should be installed.
Index: option-groups.defaults
===================================================================
--- option-groups.defaults	(revision 158625)
+++ option-groups.defaults	(working copy)
@@ -9,3 +9,4 @@
 #
 # By default, all option groups are enabled.
 OPTION_EGLIBC_CATGETS = y
+OPTION_EGLIBC_LOCALES = y

ChangeLog.eglibc:
2006-12-26  Jim Blandy  <jimb@xxxxxxxxxxxxxxxx>

       * Makefile.in: Include option-groups.mak from glibc.  Trim
       locale list if OPTION_EGLIBC_LOCALES is not enabled.

Index: Makefile.in
===================================================================
--- Makefile.in	(revision 158625)
+++ Makefile.in	(working copy)
@@ -118,8 +118,15 @@
 #----------------------------------------------------------------------------
 # Based on localedata/Makefile
 #----------------------------------------------------------------------------
+.. = glibc/
+include glibc/option-groups.mak
 include glibc/localedata/SUPPORTED
 
+# Only install locale data if OPTION_EGLIBC_LOCALES is selected.
+ifneq ($(OPTION_EGLIBC_LOCALES),y)
+SUPPORTED-LOCALES :=
+endif
+
 INSTALL-SUPPORTED-LOCALES=$(addprefix install-, $(SUPPORTED-LOCALES))
 
 LOCALEDEF=\