set _XOPEN_SOURCE=0 when building ICU
set _XOPEN_SOURCE=0 when building ICU

Today I learned -dD -E is the super-power version of -dM -E.

Change-Id: Ib8f6f426006261638f2a97ed9053bbe228f301bb
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/313166
Reviewed-by: Ben Wagner <53965154ffeecc4a10886eab9259e95965f2979a@google.com>
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>

aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia