Fix variables expansion in build/mac/asan.gyp

BUG=344836, 235466
TBR=thakis@chromium.org

Review URL: https://codereview.chromium.org/232723003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@262980 0039d316-1c4b-4281-b951-d872f2087c98

build/mac/asan.gyp

@@ -37,8 +37,12 @@
              {
                'destination': '<(PRODUCT_DIR)',
                'target_conditions': [
-                 ['_toolset=="host"', { 'files': [ 'asan_osx_dynamic'] }], 
-                 ['_toolset=="target"', { 'files': [ 'asan_iossim_dynamic'] }], 
+                 ['_toolset=="host"', {
+                   'files': [ '<!(/bin/ls <(asan_osx_dynamic))'],
+                 }],
+                 ['_toolset=="target"', {
+                   'files': [ '<!(/bin/ls <(asan_iossim_dynamic))'],
+                 }],
                ],
              },
            ],