Make "use namespace HH\Lib" in open source projects oss-only

Summary:
This makes them commented out inside Facebook's www repository, but uncomments them externally.

This is needed because of FB-specific problems with making HSL built-in: we will be temporarily
renaming HH\Lib to FlibSL internally, however the way we package externally (no monorepo, tagged
release with version constraints) means this shouldn't be shipped externally.

```
find flib/intern/diffs/difflib/opensource flib/thrift/core flib/intern/opensource/shipit -type f | xargs sed -i 's,^use namespace,// oss-enable: use namespace,'
```

Internally, we depend on the namespace aliasing feature, which is only viable for monorepos.

Reviewed By: periodic1236

Differential Revision: D27595266

fbshipit-source-id: 9302343c2f83493ec75423c291c6a9fb4b774c49

Author: fredemmott

src/CLIColoredUnifiedDiff.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\Str;
+use namespace HH\Lib\Str; // @oss-enable
 
 /** Create a colored diff between two strings, using standard terminal
  * escape sequences.

src/ColoredUnifiedDiff.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\{C, Str, Vec};
+use namespace HH\Lib\{C, Str, Vec}; // @oss-enable
 
 /** Base class for colorizing diffs.
  *

src/Diff.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\{C, Dict, Vec};
+use namespace HH\Lib\{C, Dict, Vec}; // @oss-enable
 
 /** An implementation of Myer's diff algorithm.
  *

src/StringDiff.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\{C, Str, Vec};
+use namespace HH\Lib\{C, Str, Vec}; // @oss-enable
 
 /** Concrete instance of `Diff` for comparing sequences of strings.
  *

src/cluster.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\{C, Vec};
+use namespace HH\Lib\{C, Vec}; // @oss-enable
 
 /** Group sequential operations of the same kind into one.
  *

tests/ClusterTest.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\{C, Vec};
+use namespace HH\Lib\{C, Vec}; // @oss-enable
 // @oss-disable: use function \expect;
 use function Facebook\FBExpect\expect; // @oss-enable
 

tests/RawDiffTest.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\{C, Vec};
+use namespace HH\Lib\{C, Vec}; // @oss-enable
 // @oss-disable: use function \expect;
 use function Facebook\FBExpect\expect; // @oss-enable
 

tests/StringDiffTest.php

@@ -10,7 +10,7 @@
 
 namespace Facebook\DiffLib;
 
-use namespace HH\Lib\{C, Str, Vec};
+use namespace HH\Lib\{C, Str, Vec}; // @oss-enable
 // @oss-disable: use function \expect;
 use function Facebook\FBExpect\expect; // @oss-enable