Add comment that application build implies shared library build

Author: hoodmane

peps/pep-0783.rst

@@ -105,7 +105,7 @@ The PyEmscripten Platform
 The specification of the ``pyemscripten_${YEAR}_${PATCH}`` platform includes:
 
 * Which version of the Emscripten compiler is used
-* What libraries are statically linked to the binary
+* What libraries are statically linked to the application
 * What stack unwinding ABI is to be used
 * How the loader handles dependency lookup
 * That libraries cannot use ``-pthread``
@@ -122,6 +122,12 @@ plan to use each platform with.
 The PyEmscripten platforms are fully specified in
 `Pyodide's documentation on the PyEmscripten Platform <https://pyodide.org/en/stable/development/abi.html>`__.
 
+To define the platform we need only indicate how the main application is
+compiled and linked. This implies how to build a compatible shared library.
+However, our documentation includes detailed instructions on how to build a
+compatible shared library because we assume most people will be building shared
+libraries.
+
 The ``pyodide build`` tool knows how to create wheels that are compatible with the
 PyEmscripten platform. Unlike with manylinux wheels, there is no need for a
 Docker container to build ``pyemscripten`` wheels. All that is needed is a Linux