Implement support for definition target type aliases

For example:

define cli=file

Currently, the semantics is that of a real alias with only name differences
that are used for display. See tests/define/buildfile for more use cases.

1 files changed, 3 insertions, 1 deletions

diff --git a/build/utility b/build/utility
index 42d7f0f..7e6b0df 100644
--- a/build/utility
+++ b/build/utility
@@ -7,7 +7,7 @@
 
 #include <tuple>
 #include <string>
-#include <utility>
+#include <utility> // move()
 #include <exception>
 #include <unordered_set>
 
@@ -15,6 +15,8 @@
 
 namespace build
 {
+  using std::move;
+
   // Empty string and path.
   //
   extern const std::string empty_string;