--- Python-3.7.3/Modules/getpath.c.orig	2019-03-25 21:21:05.000000000 +0100
+++ Python-3.7.3/Modules/getpath.c	2019-04-16 21:51:06.279967700 +0200
@@ -959,6 +1091,36 @@
     memset(exec_prefix, 0, sizeof(exec_prefix));
     calculate_exec_prefix(core_config, calculate, exec_prefix);
 
+#ifdef MS_WINDOWS
+    if (calculate->path_env) {
+        wchar_t *module_path, *norm_path;
+        // Add path of executable/dll to system path. This
+        // is so that the correct tcl??.dll and tk??.dll get used.
+        module_path = config->dll_path[0] ? config->dll_path : config->program_full_path;
+        norm_path = (wchar_t *)alloca(sizeof(wchar_t) * (wcslen(module_path) + 1));
+        if (norm_path) {
+            wchar_t *slashes, *end, *new_path;
+            wcscpy(norm_path, module_path);
+            slashes = wcschr(norm_path, L'/');
+            while (slashes) {
+                *slashes = L'\\';
+                slashes = wcschr(slashes + 1, L'/');
+            }
+            end = wcsrchr(norm_path, L'\\') ? wcsrchr(norm_path, L'\\') : norm_path + wcslen(norm_path);
+            end[1] = L'\0';
+
+            new_path = (wchar_t *)alloca(sizeof(wchar_t) * (wcslen(L"PATH=") + wcslen(calculate->path_env) + 1 + wcslen(norm_path) + 1));
+            if (new_path) {
+                wcscpy(new_path, L"PATH=");
+                wcscat(new_path, calculate->path_env);
+                wcscat(new_path, L";");
+                wcscat(new_path, norm_path);
+                _wputenv(new_path);
+            }
+        }
+    }
+#endif
+
     if ((!calculate->prefix_found || !calculate->exec_prefix_found) &&
         !Py_FrozenFlag)
     {