Move Metadatum::toUint32() implementation out of header file.

include/exiv2/metadatum.hpp

@@ -226,9 +226,7 @@ namespace Exiv2 {
         /*!
           @brief Return the <EM>n</EM>-th component of the value converted to uint32_t.
          */
-        uint32_t toUint32(long n =0) const {
-            return static_cast<uint32_t>(toInt64(n));
-        }
+        uint32_t toUint32(long n =0) const;
         /*!
           @brief Return the <EM>n</EM>-th component of the value converted to float.
                  The return value is -1 if the value is not set and the behaviour

src/metadatum.cpp

@@ -42,6 +42,10 @@ namespace Exiv2 {
         return os.str();
     }
 
+    uint32_t Metadatum::toUint32(long n) const {
+        return static_cast<uint32_t>(toInt64(n));
+    }
+
     bool cmpMetadataByTag(const Metadatum& lhs, const Metadatum& rhs)
     {
         return lhs.tag() < rhs.tag();