Move to Weld as the build system.

Change-Id: I7c9704f3f310cf7e5410db148a9c4c589914b0f2
diff --git a/mod/catch/def.mk b/mod/catch/def.mk
new file mode 100644
index 0000000..4573bb0
--- /dev/null
+++ b/mod/catch/def.mk
@@ -0,0 +1,6 @@
+name := catch
+lang := cpp
+type := lib
+
+header_list := catch.hpp
+source_list := catch.cpp
diff --git a/mod/3rdparty/catch/catch.hpp b/mod/catch/include/catch.hpp
similarity index 100%
rename from mod/3rdparty/catch/catch.hpp
rename to mod/catch/include/catch.hpp
diff --git a/mod/catch/source/catch.cpp b/mod/catch/source/catch.cpp
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/mod/catch/source/catch.cpp
diff --git a/mod/greeting/def.mk b/mod/greeting/def.mk
new file mode 100644
index 0000000..bd4a6cd
--- /dev/null
+++ b/mod/greeting/def.mk
@@ -0,0 +1,6 @@
+name := greeting
+lang := cpp
+type := lib
+
+header_list := greeting.hpp
+source_list := greeting.cpp
diff --git a/mod/greeting.hpp b/mod/greeting/include/greeting.hpp
similarity index 100%
rename from mod/greeting.hpp
rename to mod/greeting/include/greeting.hpp
diff --git a/mod/greeting.cpp b/mod/greeting/source/greeting.cpp
similarity index 88%
rename from mod/greeting.cpp
rename to mod/greeting/source/greeting.cpp
index 62ebb2d..0fb811d 100644
--- a/mod/greeting.cpp
+++ b/mod/greeting/source/greeting.cpp
@@ -1,4 +1,4 @@
-#include "greeting.hpp"
+#include <greeting/greeting.hpp>
 
 #include <sstream>