diff --git a/ci/run.sh b/ci/run.sh
index 34b8e76dcd..5555422765 100755
--- a/ci/run.sh
+++ b/ci/run.sh
@@ -11,8 +11,14 @@ if [ -z "$NO_RUN" ]; then
     cargo test --target $TARGET
     cargo test --target $TARGET --features static-curl
     cargo test --target $TARGET --features static-curl,protocol-ftp
+
+    # Note that `-Clink-dead-code` is passed here to suppress `--gc-sections` to
+    # help confirm that we're compiling everything necessary for curl itself.
+    RUSTFLAGS=-Clink-dead-code \
     cargo run --manifest-path systest/Cargo.toml --target $TARGET
+    RUSTFLAGS=-Clink-dead-code \
     cargo run --manifest-path systest/Cargo.toml --target $TARGET --features curl-sys/static-curl,curl-sys/protocol-ftp
+
     cargo doc --no-deps --target $TARGET
     cargo doc --no-deps -p curl-sys --target $TARGET
 fi
diff --git a/curl-sys/build.rs b/curl-sys/build.rs
index a3ec2cff75..482bfe48ab 100644
--- a/curl-sys/build.rs
+++ b/curl-sys/build.rs
@@ -133,6 +133,7 @@ fn main() {
         .file("curl/lib/asyn-thread.c")
         .file("curl/lib/altsvc.c")
         .file("curl/lib/base64.c")
+        .file("curl/lib/bufref.c")
         .file("curl/lib/conncache.c")
         .file("curl/lib/connect.c")
         .file("curl/lib/content_encoding.c")
@@ -202,6 +203,7 @@ fn main() {
         .file("curl/lib/urlapi.c")
         .file("curl/lib/version.c")
         .file("curl/lib/vauth/digest.c")
+        .file("curl/lib/vauth/vauth.c")
         .file("curl/lib/vtls/keylog.c")
         .file("curl/lib/vtls/vtls.c")
         .file("curl/lib/warnless.c")