Fix Pad compilation for clang.

include/aidge/operator/Pad.hpp

@@ -35,19 +35,6 @@ enum class PadAttr {
     BorderType,      ///< Type of border handling during padding.
     BorderValue      ///< Value to be used for constant padding.
 };
-
-namespace {
-    /**
-     * @brief EnumStrings specialization for PadAttr.
-     */
-    template <>
-    const char* const EnumStrings<Aidge::PadAttr>::data[] = {
-        "begin_end_borders",
-        "border_type",
-        "border_value"
-    };
-}  // namespace
-
 /**
  * @enum PadBorderType
  * @brief Types of border handling available for padding.
@@ -59,7 +46,20 @@ enum class PadBorderType {
     Wrap,     ///< Values wrap around the tensor dimensions.
     Zero      ///< All out-of-bound values are set to 0.
 };
+
 } // namespace Aidge
+
+namespace {
+    /**
+     * @brief EnumStrings specialization for PadAttr.
+     */
+    template <>
+    const char* const EnumStrings<Aidge::PadAttr>::data[] = {
+        "begin_end_borders",
+        "border_type",
+        "border_value"
+    };
+
 /**
  * @brief EnumStrings specialization for PadBorderType.
  */
@@ -71,6 +71,8 @@ const char* const EnumStrings<Aidge::PadBorderType>::data[] = {
     "Wrap",
     "Zero"
 };
+} // namespace
+
 namespace Aidge {
 /**
  * @class Pad_Op