Shared library is missing executable bit

[tiran]

RustExtension() creates a shared library without executable bit. Shared library on Linux, macOS, and probably other Unix-like operation systems must have executable bit. Kernel may refuse to mmap() shared libraries as PROT_EXEC.

See #106

$ ldd ./build/lib.linux-x86_64-3.9/cryptography/hazmat/bindings/_rust.abi3.so
ldd: warning: you do not have execution permission for `./build/lib.linux-x86_64-3.9/cryptography/hazmat/bindings/_rust.abi3.so'
        linux-vdso.so.1 (0x00007ffce3347000)
        libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f5702f8a000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f5702f68000)
        libc.so.6 => /lib64/libc.so.6 (0x00007f5702d9d000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f5703026000)
$ ls -la ./build/lib.linux-x86_64-3.9/cryptography/hazmat/bindings/*.so
-rwxrwxr-x. 1 heimes heimes 2669672 Feb 10 13:32 ./build/lib.linux-x86_64-3.9/cryptography/hazmat/bindings/_openssl.abi3.so
-rwxrwxr-x. 1 heimes heimes   34400 Feb 10 13:32 ./build/lib.linux-x86_64-3.9/cryptography/hazmat/bindings/_padding.abi3.so
-rw-rw-r--. 1 heimes heimes 3708904 Feb 10 13:32 ./build/lib.linux-x86_64-3.9/cryptography/hazmat/bindings/_rust.abi3.so

[tiran]

setuptools-rust/setuptools_rust/build.py

Lines 328 to 332 in 991de4c

	# executables and win32(cygwin)-dll's need X bits
	if executable or sys.platform == "win32" or sys.platform == "cygwin":
	mode = os.stat(ext_path).st_mode
	mode |= (mode & 0o444) >> 2 # copy R bits to X
	os.chmod(ext_path, mode)