Move libcxx to our fork

Change-Id: I766a212d8b03864c4f15376895110f66800340d8
diff --git a/default.xml b/default.xml
index aa9eb05..443b469 100644
--- a/default.xml
+++ b/default.xml
@@ -206,7 +206,7 @@
   <project path="external/libcap-ng" name="platform/external/libcap-ng" groups="pdk" remote="aosp" />
   <project path="external/libchrome" name="platform/external/libchrome" groups="pdk" remote="aosp" />
   <project path="external/libcups" name="platform/external/libcups" groups="pdk-cw-fs,pdk-fs" remote="aosp" />
-  <project path="external/libcxx" name="platform/external/libcxx" groups="pdk" remote="aosp" />
+  <project path="external/libcxx" name="LineageOS/android_external_libcxx" groups="pdk" />
   <project path="external/libcxxabi" name="platform/external/libcxxabi" groups="pdk" remote="aosp" />
   <project path="external/libdaemon" name="platform/external/libdaemon" groups="pdk" remote="aosp" />
   <project path="external/libdivsufsort" name="platform/external/libdivsufsort" groups="pdk" remote="aosp" />