diff --git a/CMakeLists.txt b/CMakeLists.txt
index c5b1fd81..ae70cc9d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -366,13 +366,11 @@ if(WIN32)
     endif()
 
     if(MSVC)
-        # turn off various warnings
-        # foreach(warning 4244 4251 4267 4275 4290 4786 4305 4996)
-        #     SET(WARNING_FLAGS "${WARNING_FLAGS} /wd${warning}")
-        # endforeach(warning)
+        set(MSVC_FLAGS "-DWIN32 -DNOMINMAX -D_USE_MATH_DEFINES -D_CRT_SECURE_NO_WARNINGS -D__CRT_NONSTDC_NO_WARNINGS /MP")
 
-        set(MSVC_FLAGS "-DWIN32 -DNOMINMAX -D_USE_MATH_DEFINES -D_CRT_SECURE_NO_WARNINGS -D__CRT_NONSTDC_NO_WARNINGS /wd4996 /wd4250")
         if (${MSVC_VERSION} GREATER 1599)
+          # needed to avoid link errors on multiply-defined standard C++
+          # symbols. Suspect this may be an OSG-DB export bug
             set( MSVC_LD_FLAGS "/FORCE:MULTIPLE" )
         endif (${MSVC_VERSION} GREATER 1599)
 
diff --git a/simgear/compiler.h b/simgear/compiler.h
index f6bdc37c..ab275061 100644
--- a/simgear/compiler.h
+++ b/simgear/compiler.h
@@ -61,12 +61,14 @@
 // Microsoft compilers.
 //
 #ifdef _MSC_VER
-#  define bcopy(from, to, n) memcpy(to, from, n)
+#  define strcasecmp stricmp
 
 #  if _MSC_VER >= 1200 // msvc++ 6.0 up to MSVC2013
 #    if _MSC_VER < 1900
+#      define bcopy(from, to, n) memcpy(to, from, n)
 #      define snprintf _snprintf
 #      define strdup _strdup
+#      define copysign _copysign
 #    endif
 #    if _MSC_VER < 1800
 #      define isnan _isnan
@@ -74,21 +76,18 @@
 #    if _MSC_VER < 1500
 #      define vsnprintf _vsnprintf
 #    endif
-#    define copysign _copysign
-#    define strcasecmp stricmp
-
-#    undef min
-#    undef max
 
 #    pragma warning(disable: 4786) // identifier was truncated to '255' characters
 #    pragma warning(disable: 4244) // conversion from double to float
-#    pragma warning(disable: 4305) // truncation from larer type to smaller
+#    pragma warning(disable: 4305) // truncation from larger type to smaller
+#    pragma warning(disable: 4267) // conversion from size_t to int / 32-bit type
+#    pragma warning(disable: 4996) // don't require _ prefix for standard library functions
+#    pragma warning(disable: 4800) // don't warn about int -> bool performance
 
 #  else
 #    error What version of MSVC++ is this?
 #  endif
-
-#    define SG_COMPILER_STR "Microsoft Visual C++ version " SG_STRINGIZE(_MSC_VER)
+#  define SG_COMPILER_STR "Microsoft Visual C++ version " SG_STRINGIZE(_MSC_VER)
 
 #endif // _MSC_VER
 
diff --git a/simgear/package/untar.cxx b/simgear/package/untar.cxx
index 7698029d..14ba27ce 100644
--- a/simgear/package/untar.cxx
+++ b/simgear/package/untar.cxx
@@ -278,6 +278,10 @@ TarExtractor::TarExtractor(const SGPath& rootPath) :
     d->zlibStream.next_out = d->zlibOutput;
 }
 
+TarExtractor::~TarExtractor()
+{
+}
+
 void TarExtractor::extractBytes(const char* bytes, size_t count)
 {
     if (d->state >= TarExtractorPrivate::ERROR_STATE) {
diff --git a/simgear/package/untar.hxx b/simgear/package/untar.hxx
index 76cc1f9d..0b653a67 100644
--- a/simgear/package/untar.hxx
+++ b/simgear/package/untar.hxx
@@ -34,6 +34,7 @@ class TarExtractor
 {
 public:
     TarExtractor(const SGPath& rootPath);
+	~TarExtractor();
 
     void extractBytes(const char* bytes, size_t count);