Fix system icu build.

It turns out that Skia's gn 'system' and 'third_party' templates differ
in the way public defines are declared. This also updates the build to
add libdl when building SkOSLibrary_posix.cpp, since that uses dlsym.
The current build depends on icu bringing in this dependency.

BUG=skia:7008

Change-Id: Ia710a335e1da9580f85f133a5a171f640b36ee75
Reviewed-on: https://skia-review.googlesource.com/41745
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Yuqian Li <liyuqian@google.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 0e4c0715f6..e7a495a02e 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -760,6 +760,7 @@ component("skia") {
       "src/ports/SkOSLibrary_posix.cpp",
       "src/ports/SkTLS_pthread.cpp",
     ]
+    libs += [ "dl" ]
   }
 
   if (is_android) {