Revert "Update libc and libloading"

This reverts commit bfcf97bd83.

It causes a "can't resolve symbol" crash on macOS

Cargo.lock

@@ -206,15 +206,15 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.86"
+version = "0.2.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b7282d924be3275cec7f6756ff4121987bc6481325397dde6ba3e7802b1a8b1c"
+checksum = "7ccac4b00700875e6a07c6cde370d44d32fa01c5a65cdd2fca6858c479d28bb3"
 
 [[package]]
 name = "libloading"
-version = "0.7.0"
+version = "0.6.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6f84d96438c15fcd6c3f244c8fce01d1e2b9c6b5623e9c711dc9286d8fc92d6a"
+checksum = "351a32417a12d5f7e82c368a66781e307834dae04c6ce0cd4456d52989229883"
 dependencies = [
  "cfg-if",
  "winapi",

Cargo.toml

@@ -20,7 +20,7 @@ object = { version = "0.23.0", default-features = false, features = ["std", "rea
 
 ar = { git = "https://github.com/bjorn3/rust-ar.git", branch = "do_not_remove_cg_clif_ranlib" }
 indexmap = "1.0.2"
-libloading = { version = "0.7.0", optional = true }
+libloading = { version = "0.6.0", optional = true }
 smallvec = "1.6.1"
 
 # Uncomment to use local checkout of cranelift

src/driver/jit.rs

@@ -210,7 +210,7 @@ fn load_imported_symbols_for_jit(tcx: TyCtxt<'_>) -> Vec<(String, *const u8)> {
     let mut imported_symbols = Vec::new();
     for path in dylib_paths {
         use object::{Object, ObjectSymbol};
-        let lib = unsafe { libloading::Library::new(&path).unwrap() };
+        let lib = libloading::Library::new(&path).unwrap();
         let obj = std::fs::read(path).unwrap();
         let obj = object::File::parse(&obj).unwrap();
         imported_symbols.extend(obj.dynamic_symbols().filter_map(|symbol| {