Add platform/external/libmicrohttpd

Bug: 22828501
diff --git a/default.xml b/default.xml
index 9a4870a..7d54936 100644
--- a/default.xml
+++ b/default.xml
@@ -190,6 +190,7 @@
   <project path="external/libhevc" name="platform/external/libhevc" />
   <project path="external/libgsm" name="platform/external/libgsm" groups="pdk" />
   <project path="external/liblzf" name="platform/external/liblzf" groups="pdk" />
+  <project path="external/libmicrohttpd" name="platform/external/libmicrohttpd" />
   <project path="external/libmpeg2" name="platform/external/libmpeg2" />
   <project path="external/libmtp" name="platform/external/libmtp" groups="pdk-cw-fs" />
   <project path="external/libnfc-nci" name="platform/external/libnfc-nci" groups="pdk" />