Build fails on armv7

[codeandkey]

Can't get this crate to compile on my pi -- it does compile on the same toolchain for x86_64 though.

Host info:

Linux pi 4.14.50-v7+ #1122 SMP Tue Jun 19 12:26:26 BST 2018 armv7l GNU/Linux
stable-armv7-unknown-linux-gnueabihf (default)
rustc 1.29.1 (b801ae664 2018-09-20)

Build log:

 Compiling lz4 v1.23.0                                                                                        
error[E0308]: mismatched types
  --> /home/jtst/.cargo/registry/src/github.com-1ecc6299db9ec823/lz4-1.23.0/src/block/mod.rs:81:21
   |
81 |                     src.as_ptr() as *const i8,
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
   |
   = note: expected type `*const u8`
              found type `*const i8`

error[E0308]: mismatched types
  --> /home/jtst/.cargo/registry/src/github.com-1ecc6299db9ec823/lz4-1.23.0/src/block/mod.rs:82:21
   |
82 |                     dst_buf.as_mut_ptr() as *mut i8,
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
   |
   = note: expected type `*mut u8`
              found type `*mut i8`

error[E0308]: mismatched types
  --> /home/jtst/.cargo/registry/src/github.com-1ecc6299db9ec823/lz4-1.23.0/src/block/mod.rs:90:21
   |
90 |                     src.as_ptr() as *const i8,
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
   |
   = note: expected type `*const u8`
              found type `*const i8`

error[E0308]: mismatched types
  --> /home/jtst/.cargo/registry/src/github.com-1ecc6299db9ec823/lz4-1.23.0/src/block/mod.rs:91:21
   |
91 |                     dst_buf.as_mut_ptr() as *mut i8,
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
   |
   = note: expected type `*mut u8`
              found type `*mut i8`

error[E0308]: mismatched types
  --> /home/jtst/.cargo/registry/src/github.com-1ecc6299db9ec823/lz4-1.23.0/src/block/mod.rs:99:21
   |
99 |                     src.as_ptr() as *const i8,
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
   |
   = note: expected type `*const u8`
              found type `*const i8`

error[E0308]: mismatched types
   --> /home/jtst/.cargo/registry/src/github.com-1ecc6299db9ec823/lz4-1.23.0/src/block/mod.rs:100:21
    |
100 |                     dst_buf.as_mut_ptr() as *mut i8,
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
    |
    = note: expected type `*mut u8`
               found type `*mut i8`

error[E0308]: mismatched types
   --> /home/jtst/.cargo/registry/src/github.com-1ecc6299db9ec823/lz4-1.23.0/src/block/mod.rs:164:13
    |
164 |             src.as_ptr() as *const i8,
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
    |
    = note: expected type `*const u8`
               found type `*const i8`

error[E0308]: mismatched types
   --> /home/jtst/.cargo/registry/src/github.com-1ecc6299db9ec823/lz4-1.23.0/src/block/mod.rs:165:13
    |
165 |             decompressed.as_mut_ptr() as *mut i8,
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
    |
    = note: expected type `*mut u8`
               found type `*mut i8`

[jheyens]

I see, where this is coming from, since we are "lying" to C about what kind of char ptr we got here. I'll see if I can reproduce this on Qemu systems.
Thanks!

[jheyens]

Fixed on master. I'll close this issue once I publish the next version to crates.io.

The error was due to lz4-sys C bindings using *c_char pointers, where c_char is i8 on x86 and u8 on arm.

[jheyens]

Uploaded to crates.io.

Sorry for the delay.