build: fix icutrim when building small-icu on BE

Fix a build error that occurs when icutrim is run to cut down
the ICU locale set on Big-Endian platforms when building with
--with-intl=small-icu (which is done by the "make binary" target).
This fixes the binary build on POWER platforms.

Fixes: #2601
PR-URL: #2602
Reviewed-By: Steven Loomis <srloomis@us.ibm.com>

tools/icu/icu-generic.gyp

@@ -29,9 +29,17 @@
       'type': 'none',
       'toolsets': [ 'host', 'target' ],
       'direct_dependent_settings': {
+        'conditions': [
+          [ 'icu_endianness == "l"', {
+             'defines': [
+                # ICU cannot swap the initial data without this.
+                # http://bugs.icu-project.org/trac/ticket/11046
+                'UCONFIG_NO_LEGACY_CONVERSION=1',
+                'UCONFIG_NO_IDNA=1',
+             ],
+          }],
+        ],
         'defines': [
-          'UCONFIG_NO_LEGACY_CONVERSION=1',
-          'UCONFIG_NO_IDNA=1',
           'UCONFIG_NO_TRANSLITERATION=1',
           'UCONFIG_NO_SERVICE=1',
           'UCONFIG_NO_REGULAR_EXPRESSIONS=1',