Generate sh-compatible binstubs on Unix.

sdk/lib/_internal/pub/lib/src/global_packages.dart

Index: sdk/lib/_internal/pub/lib/src/global_packages.dart
diff --git a/sdk/lib/_internal/pub/lib/src/global_packages.dart b/sdk/lib/_internal/pub/lib/src/global_packages.dart
index 2c06069f772ba6f824ad5ce99757d2056357e5ae..2a20acaf1e4573148c9a5733ac0b83393ab1d673 100644
--- a/sdk/lib/_internal/pub/lib/src/global_packages.dart
+++ b/sdk/lib/_internal/pub/lib/src/global_packages.dart
@@ -694,7 +694,7 @@ $invocation "\$@"
 # The VM exits with code 255 if the snapshot version is out-of-date.
 # If it is, we need to delete it and run "pub global" manually.
 exit_code=\$?
-if [[ \$exit_code != 255 ]]; then
+if [ \$exit_code != 255 ]; then

[ahe, 2014/12/12 09:04:42]

If you want this to work in non-bash shells, then you should get in the habit of
quoting variables:

if [ "\$exit_code" != 255 ]; then

In this specific case it doesn't matter, but generally, older shells will behave
differently from bash if you don't quote variables. For example, if $exit_code
is empty or undefined, some shells will parse it as:

if [ != 255 ]; then

Which leads to an error.

   exit \$exit_code
 fi