Add GMP and MPFR math to platform

Introduce a GMP-backed BigInt/BigFloat module, wire host exports, and add Chudnovsky pi via Math.pi!.

Author: Your Name

Cargo.lock

@@ -12,6 +12,7 @@ members = [
     "crates/roc_env",
     "crates/roc_sqlite",
     "crates/roc_random",
+    "crates/roc_gmp",
 ]
 
 [workspace.package]
@@ -40,6 +41,8 @@ roc_stdio = { path = "crates/roc_stdio" }
 roc_env = { path = "crates/roc_env" }
 roc_random = { path = "crates/roc_random" }
 roc_sqlite = { path = "crates/roc_sqlite" }
+roc_gmp = { path = "crates/roc_gmp" }
+rug = "=1.26.0"
 memchr = "=2.7.4"
 hyper = { version = "=1.6.0", default-features = false, features = [
     "http1",

Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "roc_gmp"
+description = "Common functionality for Roc to interface with GMP via rug"
+
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+version.workspace = true
+
+[dependencies]
+roc_std.workspace = true
+roc_std_heap.workspace = true
+rug.workspace = true