Implement support for pre-processing version headers (or other files)

Also implement the build system version check.

1 files changed, 17 insertions, 0 deletions

diff --git a/build2/version/rule b/build2/version/rule
index 75a8c12..186df59 100644
--- a/build2/version/rule
+++ b/build2/version/rule
@@ -30,6 +30,23 @@ namespace build2
       static target_state
       perform_update (action, const target&);
     };
+
+    // Preprocess an .in file.
+    //
+    class version_in: public rule
+    {
+    public:
+      version_in () {}
+
+      virtual match_result
+      match (action, target&, const string&) const override;
+
+      virtual recipe
+      apply (action, target&) const override;
+
+      static target_state
+      perform_update (action, const target&);
+    };
   }
 }