diff --git a/Cargo.lock b/Cargo.lock
index c408a5c..d7eaa5b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -117,6 +117,7 @@ version = "0.3.0+55.0"
 dependencies = [
  "bindgen",
  "cmake",
+ "proc-macro2",
  "regex",
 ]
 
diff --git a/ibverbs-sys/Cargo.toml b/ibverbs-sys/Cargo.toml
index c662d32..222ba24 100644
--- a/ibverbs-sys/Cargo.toml
+++ b/ibverbs-sys/Cargo.toml
@@ -29,4 +29,5 @@ cmake = "0.1.50"
 
 # to make -Zminimal-versions work
 [target.'cfg(any())'.dependencies]
-regex = "1.6"
+regex = { version = "1.6", optional = true }
+proc-macro2 = { version = "1.0.80", optional = true }