Fix compilation error from extern template being removed

Clang-tidy must have though these were obselete (which they are on every platform
but OSX), so protect them with a macro and add them back

Framework/PythonInterface/core/src/Converters/CloneToNDArray.cpp

@@ -19,7 +19,20 @@
 #define NO_IMPORT_ARRAY
 #include <numpy/arrayobject.h>
 
-namespace Mantid::PythonInterface::Converters::Impl {
+namespace Mantid::PythonInterface::Converters {
+#ifdef __APPLE__
+extern template int NDArrayTypeIndex<bool>::typenum;
+extern template int NDArrayTypeIndex<int>::typenum;
+extern template int NDArrayTypeIndex<long>::typenum;
+extern template int NDArrayTypeIndex<long long>::typenum;
+extern template int NDArrayTypeIndex<unsigned int>::typenum;
+extern template int NDArrayTypeIndex<unsigned long>::typenum;
+extern template int NDArrayTypeIndex<unsigned long long>::typenum;
+extern template int NDArrayTypeIndex<float>::typenum;
+extern template int NDArrayTypeIndex<double>::typenum;
+extern template int NDArrayTypeIndex<Mantid::Types::Core::DateAndTime>::typenum;
+#endif
+namespace Impl {
 /**
  * Returns a new numpy array with the a copy of the data from 1D vector with the
  * exception of string elements where a Python list is produced
@@ -151,4 +164,5 @@ INSTANTIATE_CLONEND(Types::Core::DateAndTime)
 // Need further ND specialisation for bool
 INSTANTIATE_CLONEND(bool)
 ///@endcond
-} // namespace Mantid::PythonInterface::Converters::Impl
+} // namespace Impl
+} // namespace Mantid::PythonInterface::Converters

Framework/PythonInterface/core/src/Converters/WrapWithNDArray.cpp

@@ -31,7 +31,19 @@ template <typename T> void capsule_cleanup(PyObject *capsule) {
 
 } // namespace
 
-namespace Mantid::PythonInterface::Converters::Impl {
+namespace Mantid::PythonInterface::Converters {
+#ifdef __APPLE__
+extern template int NDArrayTypeIndex<bool>::typenum;
+extern template int NDArrayTypeIndex<int>::typenum;
+extern template int NDArrayTypeIndex<long>::typenum;
+extern template int NDArrayTypeIndex<long long>::typenum;
+extern template int NDArrayTypeIndex<unsigned int>::typenum;
+extern template int NDArrayTypeIndex<unsigned long>::typenum;
+extern template int NDArrayTypeIndex<unsigned long long>::typenum;
+extern template int NDArrayTypeIndex<float>::typenum;
+extern template int NDArrayTypeIndex<double>::typenum;
+#endif
+
 namespace {
 /**
  * Flip the writable flag to ensure the array is read only
@@ -48,6 +60,8 @@ void markReadOnly(PyArrayObject *arr) {
 }
 } // namespace
 
+namespace Impl {
+
 /**
  * Defines the wrapWithNDArray specialization for C array types
  *
@@ -95,4 +109,5 @@ INSTANTIATE_WRAPNUMPY(unsigned long long)
 INSTANTIATE_WRAPNUMPY(double)
 INSTANTIATE_WRAPNUMPY(float)
 ///@endcond
-} // namespace Mantid::PythonInterface::Converters::Impl
+} // namespace Impl
+} // namespace Mantid::PythonInterface::Converters
\ No newline at end of file