Update text about cross compilation

Author: hoodmane

peps/pep-0776.rst

@@ -709,8 +709,10 @@ Improving Cross Builds in the Packaging Ecosystem
 Python now supports four non-self-hosting platforms: iOS, Android, WASI, and
 Emscripten. All of them will need to build packages via cross builds. Currently,
 ``pyodide-build`` allows building a very large number of Python packages for
-Emscripten, but it relies on a giant pile of hacks. In the long run, we would
-like to make the packaging ecosystem support cross builds in a sane way.
+Emscripten, but it is very complicated. Ideally, the Python packaging ecosystem
+would have standards for cross builds. This is a difficult long term project,
+particularly because the packaging system is complex and was designed from the
+ground up with the assumption that cross compilation would not happen.
 
 
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