Crate not usable on arm/android any more

[MagaTailor]

The reason being this.

Compiling freetype-rs v0.4.0
/home/odroid/.cargo/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.0/src/face.rs:81:43: 81:77 error: mismatched types:
 expected `*const u8`,
    found `*const i8`
(expected u8,
    found i8) [E0308]
/home/odroid/.cargo/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.0/src/face.rs:81             ffi::FT_Attach_File(self.raw, filepathname.as_ptr() as *const i8)
                                                                                                                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/odroid/.cargo/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.0/src/face.rs:81:43: 81:77 help: run `rustc --explain E0308` to see a detailed explanation
error: aborting due to previous error

[bvssvni]

@petevine Can you test this? We could try filepathname.as_ptr() as *const _.

[MagaTailor]

It does compile - I haven't seen this solution yet (a couple of crates have been fixed so far).
Isn't it too permissive or prone to some new kind of error in the future?

EDIT:
I didn't pay attention to version history - was 0.4.0 new enough? (i.e. using libc 0.2?)

[bvssvni]

@petevine Did the error happen on the old version of freetype-rs? Is it fixed now?

[bvssvni]

@petevine Yes, there have been upgrades to libc 0.2 that might change how it worked.

[MagaTailor]

The fix allows the current version (0.4.0) to compile.

[MagaTailor]

Forgot to try on stable 1.5:

Compiling freetype-rs v0.4.1
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:314:32: 314:43 error: mismatched types:
 expected `*const i8`,
    found `*mut u8`
(expected i8,
    found u8) [E0308]
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:314                 CStr::from_ptr(family_name).to_bytes().to_vec()
                                                                                                                          ^~~~~~~~~~~
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:314:32: 314:43 help: run `rustc --explain E0308` to see a detailed explanation
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:327:32: 327:42 error: mismatched types:
 expected `*const i8`,
    found `*mut u8`
(expected i8,
    found u8) [E0308]
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:327                 CStr::from_ptr(style_name).to_bytes().to_vec()
                                                                                                                          ^~~~~~~~~~
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:327:32: 327:42 help: run `rustc --explain E0308` to see a detailed explanation
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:352:32: 352:41 error: mismatched types:
 expected `*const i8`,
    found `*const u8`
(expected i8,
    found u8) [E0308]
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:352                 CStr::from_ptr(face_name).to_bytes().to_vec()
                                                                                                                          ^~~~~~~~~
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/face.rs:352:32: 352:41 help: run `rustc --explain E0308` to see a detailed explanation
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/library.rs:68:40: 68:53 error: mismatched types:
 expected `*const u8`,
    found `*const i8`
(expected u8,
    found i8) [E0308]
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/library.rs:68             ffi::FT_New_Face(self.raw, path.as_ptr(), face_index as ffi::FT_Long, &mut face)
                                                                                                                                    ^~~~~~~~~~~~~
/tmp/.cargo-1.5/registry/src/github.com-48ad6e4054423464/freetype-rs-0.4.1/src/library.rs:68:40: 68:53 help: run `rustc --explain E0308` to see a detailed explanation
error: aborting due to 4 previous errors

A few casts should fix that as well.