fix editable with msvc

Author: isuruf

symengine/lib/CMakeLists.txt

@@ -77,6 +77,18 @@ if (CMAKE_CXX_COMPILER_ID MATCHES GNU|Clang)
   )
 endif()
 
+if("${CMAKE_CURRENT_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_BINARY_DIR}"
+   AND DEFINED SKBUILD)
+  # Editable in-place builds. THe empty generator expression ensures
+  # multi-config enerators keeps us from having to set
+  # LIBRARY_OUTPUT_DIRECTORY_<CONFIG> too.
+  set_target_properties(
+    symengine_wrapper
+    PROPERTIES
+      LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}$<0:>"
+  )
+endif()
+
 install(
   TARGETS
     symengine_wrapper