Do not pass -no-pie to the C compiler on musl/arm64

[kit-ty-kate]

This upstreams the last non-upstreamed patch present in Alpine.

Originally added to Alpine in https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/18213 by @omnivagant

[kit-ty-kate]

I think it might be useful to have a more formal list of architectures that produce PIC objects by default somewhere in the configure.ac that would be more linked to the actual code. But I’m not sure how practical that is.

[kit-ty-kate]

The error in Appveyor doesn’t look related:

Preparing worktree (new branch 'appveyor-build-mingw64')
Updating files: 100% (3981/3981), done.
HEAD is now at c4766f3 Merge ebea50bb7f3696ec01478cc56f8eca6fc7b14d34 into 389121d30917dc2a0e2e06eca494abe28efeb38b
Submodule 'flexdll' (https://github.com/alainfrisch/flexdll.git) registered for path 'flexdll'
Cloning into 'C:/projects/🐫реализация-mingw64/flexdll'...
Submodule path 'flexdll': checked out '7aacd75e33bd34d27109bc765f40f46932716560'
Downloading flexdll.zip (875,872 bytes)...100%
        1 file(s) moved.
Cygwin Package Information
Package                 Version
cygwin                  3.1.2-1
diffutils               3.5-2
make                    4.2.1-2
mingw64-x86_64-gcc-core 7.4.0-1
bunzip2: Compressed file ends unexpectedly;
	perhaps it is corrupted?  *Possible* reason follows.
bunzip2: No error
	Input file = (stdin), output file = (stdout)
It is possible that the compressed file(s) have become corrupted.
You can use the -tvv option to test integrity of such files.
You can use the `bzip2recover' program to attempt to recover
data from undamaged sections of corrupted files.
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now

[anmonteiro]

The changelog entry mentions musl, but I'm having trouble finding the actual musl change in the patch. Is it because it was ported from alpine?

[xavierleroy]

Looks good to me. Indeed, ARM64 should be clean w.r.t. PIC. Trivial update to a comment suggested below.

[kit-ty-kate]

cc @Octachron any chance this could be backported to the 4.14 branch?

[Octachron]

I am in principle in favor (since this is a small configuration tweak before the rc).