Work around missing lib on linux (Issue #4972) (#4975)

programs/bpf/rust/128bit_dep/Cargo.toml

@@ -14,5 +14,8 @@ edition = "2018"
 [dependencies]
 solana-sdk-bpf-utils = { path = "../../../../sdk/bpf/rust/rust-utils", version = "0.17.0" }
 
+[dev_dependencies]
+solana-sdk-bpf-test = { path = "../../../../sdk/bpf/rust/rust-test", version = "0.17.0" }
+
 [workspace]
 members = []

programs/bpf/rust/128bit_dep/src/lib.rs

@@ -13,6 +13,18 @@ mod test {
     extern crate std;
     use super::*;
 
+    #[test]
+    fn pull_in_externs() {
+        // Rust on Linux excludes the solana_sdk_bpf_test library unless there is a
+        // direct dependency, use this test to force the pull in of the library.
+        // This is not necessary on macos and unfortunate on Linux
+        // Issue #4972
+        extern crate solana_sdk_bpf_test;
+        use solana_sdk_bpf_test::*;
+        unsafe { sol_log_("X".as_ptr(), 1) };
+        sol_log_64_(1, 2, 3, 4, 5);
+    }
+
     #[test]
     fn test_work() {
         assert_eq!(3, work(1, 2));