diff -urEb dcmtk-3.6.6.orig/CMake/GenerateDCMTKConfigure.cmake dcmtk-3.6.6/CMake/GenerateDCMTKConfigure.cmake
--- dcmtk-3.6.6.orig/CMake/GenerateDCMTKConfigure.cmake	2021-01-26 08:51:48.815071681 +0100
+++ dcmtk-3.6.6/CMake/GenerateDCMTKConfigure.cmake	2021-01-26 08:52:06.331135995 +0100
@@ -169,6 +169,8 @@
 endif()
 
 # Check the sizes of various types
+if (NOT CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
+  # This doesn't work for wasm, Orthanc defines the macros manually
 include (CheckTypeSize)
 CHECK_TYPE_SIZE("char" SIZEOF_CHAR)
 CHECK_TYPE_SIZE("double" SIZEOF_DOUBLE)
@@ -177,6 +179,7 @@
 CHECK_TYPE_SIZE("long" SIZEOF_LONG)
 CHECK_TYPE_SIZE("short" SIZEOF_SHORT)
 CHECK_TYPE_SIZE("void*" SIZEOF_VOID_P)
+endif()
 
 # Check for include files, libraries, and functions
 include("${DCMTK_CMAKE_INCLUDE}CMake/dcmtkTryCompile.cmake")
diff -urEb dcmtk-3.6.6.orig/dcmdata/include/dcmtk/dcmdata/dcdict.h dcmtk-3.6.6/dcmdata/include/dcmtk/dcmdata/dcdict.h
--- dcmtk-3.6.6.orig/dcmdata/include/dcmtk/dcmdata/dcdict.h	2021-01-26 08:51:48.859071844 +0100
+++ dcmtk-3.6.6/dcmdata/include/dcmtk/dcmdata/dcdict.h	2021-01-26 08:52:06.331135995 +0100
@@ -152,6 +152,12 @@
     /// returns an iterator to the end of the repeating tag dictionary
     DcmDictEntryListIterator repeatingEnd() { return repDict.end(); }
 
+    // Function by the Orthanc project to load a dictionary from a
+    // memory buffer, which is necessary in sandboxed
+    // environments. This is an adapted version of
+    // DcmDataDictionary::loadDictionary().
+    OFBool loadFromMemory(const std::string& content, OFBool errorIfAbsent = OFTrue);
+
 private:
 
     /** private undefined assignment operator
diff -urEb dcmtk-3.6.6.orig/dcmdata/libsrc/dcdicdir.cc dcmtk-3.6.6/dcmdata/libsrc/dcdicdir.cc
--- dcmtk-3.6.6.orig/dcmdata/libsrc/dcdicdir.cc	2021-01-26 08:51:48.863071859 +0100
+++ dcmtk-3.6.6/dcmdata/libsrc/dcdicdir.cc	2021-01-26 08:56:03.519887982 +0100
@@ -1032,7 +1032,14 @@
     // insert Media Stored SOP Class UID
     insertMediaSOPUID(metainfo);
 
-    getDirFileFormat().validateMetaInfo(outxfer);
+    /**
+     * Patch for Orthanc: In DCMTK 3.6.6, the default value for the
+     * second argument changed from "EWM_fileformat" to
+     * "EWM_createNewMeta". This sets "MediaStorageSOPClassUID"
+     * (0002,0002) in meta-header to "1.2.276.0.7230010.3.1.0.1"
+     * instead of expected "1.2.840.10008.1.3.10".
+     **/
+    getDirFileFormat().validateMetaInfo(outxfer, EWM_fileformat);
 
     {
         // it is important that the cache object is destroyed before the file is renamed!
diff -urEb dcmtk-3.6.6.orig/dcmdata/libsrc/dcdict.cc dcmtk-3.6.6/dcmdata/libsrc/dcdict.cc
--- dcmtk-3.6.6.orig/dcmdata/libsrc/dcdict.cc	2021-01-26 08:51:48.863071859 +0100
+++ dcmtk-3.6.6/dcmdata/libsrc/dcdict.cc	2021-01-26 08:52:06.331135995 +0100
@@ -900,3 +900,6 @@
   wrlock().clear();
   wrunlock();
 }
+
+
+#include "dcdict_orthanc.cc"
diff -urEb dcmtk-3.6.6.orig/dcmdata/libsrc/dcpxitem.cc dcmtk-3.6.6/dcmdata/libsrc/dcpxitem.cc
--- dcmtk-3.6.6.orig/dcmdata/libsrc/dcpxitem.cc	2021-01-26 08:51:48.863071859 +0100
+++ dcmtk-3.6.6/dcmdata/libsrc/dcpxitem.cc	2021-01-26 08:52:06.335136010 +0100
@@ -36,6 +36,9 @@
 #include "dcmtk/dcmdata/dcostrma.h"    /* for class DcmOutputStream */
 #include "dcmtk/dcmdata/dcwcache.h"    /* for class DcmWriteCache */
 
+#undef max
+#include "dcmtk/ofstd/oflimits.h"
+ 
 
 // ********************************
 
diff -urEb dcmtk-3.6.6.orig/oflog/include/dcmtk/oflog/thread/syncpub.h dcmtk-3.6.6/oflog/include/dcmtk/oflog/thread/syncpub.h
--- dcmtk-3.6.6.orig/oflog/include/dcmtk/oflog/thread/syncpub.h	2021-01-26 08:51:48.847071800 +0100
+++ dcmtk-3.6.6/oflog/include/dcmtk/oflog/thread/syncpub.h	2021-01-26 08:52:06.335136010 +0100
@@ -63,7 +63,7 @@
 
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 Mutex::Mutex (Mutex::Type t)
-    : mtx (DCMTK_LOG4CPLUS_THREADED (new impl::Mutex (t)) + 0)
+    : mtx (DCMTK_LOG4CPLUS_THREADED (new impl::Mutex (t)))
 { }
 
 
@@ -106,7 +106,7 @@
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 Semaphore::Semaphore (unsigned DCMTK_LOG4CPLUS_THREADED (max),
     unsigned DCMTK_LOG4CPLUS_THREADED (initial))
-    : sem (DCMTK_LOG4CPLUS_THREADED (new impl::Semaphore (max, initial)) + 0)
+    : sem (DCMTK_LOG4CPLUS_THREADED (new impl::Semaphore (max, initial)))
 { }
 
 
@@ -148,7 +148,7 @@
 
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 FairMutex::FairMutex ()
-    : mtx (DCMTK_LOG4CPLUS_THREADED (new impl::FairMutex) + 0)
+    : mtx (DCMTK_LOG4CPLUS_THREADED (new impl::FairMutex))
 { }
 
 
@@ -190,7 +190,7 @@
 
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 ManualResetEvent::ManualResetEvent (bool DCMTK_LOG4CPLUS_THREADED (sig))
-    : ev (DCMTK_LOG4CPLUS_THREADED (new impl::ManualResetEvent (sig)) + 0)
+    : ev (DCMTK_LOG4CPLUS_THREADED (new impl::ManualResetEvent (sig)))
 { }
 
 
@@ -252,7 +252,7 @@
 
 DCMTK_LOG4CPLUS_INLINE_EXPORT
 SharedMutex::SharedMutex ()
-    : sm (DCMTK_LOG4CPLUS_THREADED (new impl::SharedMutex) + 0)
+    : sm (DCMTK_LOG4CPLUS_THREADED (new impl::SharedMutex))
 { }
 
 
diff -urEb dcmtk-3.6.6.orig/oflog/libsrc/oflog.cc dcmtk-3.6.6/oflog/libsrc/oflog.cc
--- dcmtk-3.6.6.orig/oflog/libsrc/oflog.cc	2021-01-26 08:51:48.847071800 +0100
+++ dcmtk-3.6.6/oflog/libsrc/oflog.cc	2021-01-26 08:52:06.335136010 +0100
@@ -19,6 +19,10 @@
  *
  */
 
+#if defined(_WIN32)
+#  include <winsock2.h>
+#endif
+
 #include "dcmtk/config/osconfig.h"    /* make sure OS specific configuration is included first */
 #include "dcmtk/oflog/oflog.h"
 
diff -urEb dcmtk-3.6.6.orig/ofstd/include/dcmtk/ofstd/offile.h dcmtk-3.6.6/ofstd/include/dcmtk/ofstd/offile.h
--- dcmtk-3.6.6.orig/ofstd/include/dcmtk/ofstd/offile.h	2021-01-26 08:51:48.863071859 +0100
+++ dcmtk-3.6.6/ofstd/include/dcmtk/ofstd/offile.h	2021-01-26 08:52:06.335136010 +0100
@@ -586,7 +586,7 @@
    */
   void setlinebuf()
   {
-#if defined(_WIN32) || defined(__hpux)
+#if defined(_WIN32) || defined(__hpux) || defined(__LSB_VERSION__)
     this->setvbuf(NULL, _IOLBF, 0);
 #else
     :: setlinebuf(file_);