Add some missing QPDF_DLL markers

These markers are being added for nested classes that are already
marked with QPDF_DLL_CLASS. They don't make any different on Linux,
but they matter on Windows.

ChangeLog

@@ -1,5 +1,7 @@
 2022-09-12  Jay Berkenbilt  <ejb@ql.org>
 
+        * Add some missing DLL exports that only affect the Windows build.
+
         * Remove compile-time test for LL_FMT. It's unlikely that any
         compiler new enough to build qpdf still doesn't support %lld.
 

include/qpdf/InputSource.hh

@@ -47,7 +47,9 @@ class QPDF_DLL_CLASS InputSource
     class QPDF_DLL_CLASS Finder
     {
       public:
+        QPDF_DLL
         Finder() = default;
+        QPDF_DLL
         virtual ~Finder() = default;
         virtual bool check() = 0;
     };

include/qpdf/Pl_DCT.hh

@@ -41,7 +41,9 @@ class QPDF_DLL_CLASS Pl_DCT: public Pipeline
     class QPDF_DLL_CLASS CompressConfig
     {
       public:
+        QPDF_DLL
         CompressConfig() = default;
+        QPDF_DLL
         virtual ~CompressConfig() = default;
         virtual void apply(jpeg_compress_struct*) = 0;
     };

include/qpdf/QPDFWriter.hh

@@ -81,6 +81,7 @@ class QPDFWriter
     class QPDF_DLL_CLASS ProgressReporter
     {
       public:
+        QPDF_DLL
         virtual ~ProgressReporter();
 
         // This method is called with a value from 0 to 100 to
@@ -95,8 +96,11 @@ class QPDFWriter
     class QPDF_DLL_CLASS FunctionProgressReporter: public ProgressReporter
     {
       public:
+        QPDF_DLL
         FunctionProgressReporter(std::function<void(int)>);
+        QPDF_DLL
         virtual ~FunctionProgressReporter();
+        QPDF_DLL
         virtual void reportProgress(int) override;
 
       private:

manual/release-notes.rst

@@ -14,6 +14,9 @@ For a detailed list of changes, please see the file
     - Remove ``LL_FMT`` tests, which were broken for cross
       compilation. The code just uses ``%lld`` now.
 
+    - Some symbols were not properly exported for the Windows DLL
+      build.
+
 11.0.0: September 10, 2022
   - Replacement of ``PointerHolder`` with ``std::shared_ptr``