While trying to build Python 3.6.0 on emmbedded Linux device — D-Link DNS-320L running Alt-F firmware (Linux 3.18.28 #1 Fri Jun 17 14:44:39 WEST 2016 armv5tel GNU/Linux), it fails with

./python: can't resolve symbol 'crypt'
make: *** [sharedmods] Error 1

I can see the python executable is compiled fine in the source directory, if I try to run it, then it does work, including some quick tests (calculations, os.getcwd, random.randint -- works fine). 

I can also see that compiling the crypt modules did not report any errors and the .o file is present on the disk. I guess it is some kind of linking error?

Attaching the log from the build.

My patch at https://hg.python.org/cpython/rev/ca2f024ce7cb may help. It points out missing symbols earlier.

Hi Chi Hsuan Yen, thanks for trying to help, unfortunately no change, still getting the same error.

That's super strange. crypt() is used in _crypt module only, and this modules is not used elsewhere in Python. A few more tests may help diagnostics

1. What's the result of ```./python -E```?
2. Does `import crypt` run fine in ./python?
3. Are there pre-installed Python on Alt-F? Uninstall them first may help
4. Is there a symbol called crypt in `nm ./python`?

1. What's the result of ```./python -E```?

Python 3.6.0 (default, Feb 13 2017, 08:16:44)
[GCC 4.5.4 20120202 (prerelease)] on linux
Type "help", "copyright", "credits" or "license" for more information.

2. Does `import crypt` run fine in ./python?

No, gives the error
./python: can't resolve symbol 'crypt'

3. Are there pre-installed Python on Alt-F? Uninstall them first may help

No, there is no python preinstalled (no python3, not even python2)

4. Is there a symbol called crypt in `nm ./python`?

No, `nm ./python | grep crypt` gives no results

The missing “crypt” symbol is probably this function: <http://pubs.opengroup.org/onlinepubs/9699919799/functions/crypt.html>. It is defined by the OS or a separate library, not by Python. You may need to link the “_crypt” Python module to the library that contains the function. E.g. in Glibc <http://man7.org/linux/man-pages/man3/crypt.3.html> you are meant to “link with -lcrypt”, although I suspect Python’s “setup.py” normally does that automatically.

3.6 is no longer maintained, please create a new issue if you are seeing this problem on a current version (>= 3.9).