diff --git a/openssl/build.rs b/openssl/build.rs
index 15d4b4db..b67438e5 100644
--- a/openssl/build.rs
+++ b/openssl/build.rs
@@ -1,15 +1,21 @@
 use std::env;
 
 fn main() {
-    if env::var("DEP_OPENSSL_IS_101").is_ok() {
-        println!("cargo:rustc-cfg=ossl101");
-        println!("cargo:rustc-cfg=ossl10x");
+    if env::var("DEP_OPENSSL_IS_110").is_ok() {
+        println!("cargo:rustc-cfg=ossl110");
+        return;
+    } else if cfg!(feature = "openssl-110") {
+        panic!("the openssl-110 feature is enabled but OpenSSL 1.1.0+ is not being linked against");
     }
     if env::var("DEP_OPENSSL_IS_102").is_ok() {
         println!("cargo:rustc-cfg=ossl102");
         println!("cargo:rustc-cfg=ossl10x");
+        return;
+    } else if cfg!(feature = "openssl-102") {
+        panic!("the openssl-102 feature is enabled but OpenSSL 1.0.2+")
     }
-    if env::var("DEP_OPENSSL_IS_110").is_ok() {
-        println!("cargo:rustc-cfg=ossl110");
+    if env::var("DEP_OPENSSL_IS_101").is_ok() {
+        println!("cargo:rustc-cfg=ossl101");
+        println!("cargo:rustc-cfg=ossl10x");
     }
 }