diff --git a/librs/Cargo.toml b/librs/Cargo.toml
index d12d408af..397b8bd09 100644
--- a/librs/Cargo.toml
+++ b/librs/Cargo.toml
@@ -11,5 +11,28 @@ crate-type = ["staticlib"]
 [dependencies]
 rlibc = "1.0.0"	# Low-level functions like memcpy.
 spin = "0.4.5"	# Spinlocks.
-x86 = "0.8.1"	# CPU data structures.
 raw-cpuid = "3.0.0"
+
+[dependencies.x86]
+version = "0.7"
+default-features = false
+
+# The development profile, used for `cargo build`.
+[profile.dev]
+opt-level = 0      # controls the `--opt-level` the compiler builds with
+debug = true       # controls whether the compiler passes `-C debuginfo`
+                   # a value of `true` is equivalent to `2`
+rpath = false      # controls whether the compiler passes `-C rpath`
+lto = false        # controls `-C lto` for binaries and staticlibs
+debug-assertions = true # controls whether debug assertions are enabled
+codegen-units = 1  # controls whether the compiler passes `-C codegen-units`
+                   # `codegen-units` is ignored when `lto = true`
+
+# The release profile, used for `cargo build --release`.
+[profile.release]
+opt-level = 3
+debug = false
+rpath = false
+lto = true
+debug-assertions = false
+codegen-units = 1