linker: Add some function header comments
diff --git a/linker.cpp b/linker.cpp
index 6de42d3..ca0cacd 100644
--- a/linker.cpp
+++ b/linker.cpp
@@ -104,6 +104,12 @@
    bool found;             /**< Was a write to the variable found? */
 };
 
+
+/**
+ * Verify that a vertex shader executable meets all semantic requirements
+ *
+ * \param shader  Vertex shader executable to be verified
+ */
 bool
 validate_vertex_shader_executable(struct glsl_shader *shader)
 {
@@ -126,6 +132,11 @@
 }
 
 
+/**
+ * Verify that a fragment shader executable meets all semantic requirements
+ *
+ * \param shader  Fragment shader executable to be verified
+ */
 bool
 validate_fragment_shader_executable(struct glsl_shader *shader)
 {