diff --git a/openssl-sys/build.rs b/openssl-sys/build.rs
index 0388a184..e7fb3ac1 100644
--- a/openssl-sys/build.rs
+++ b/openssl-sys/build.rs
@@ -19,19 +19,13 @@ fn main() {
 
     if target.contains("win32") || target.contains("win64") || target.contains("windows") {
         println!("cargo:rustc-flags=-l crypto -l ssl -l gdi32 -l wsock32");
-        // going to assume the user has a new version of openssl
-        build_old_openssl_shim(false, vec![]);
-        return;
-    }
-
-    if let Ok(info) =  pkg_config::Config::new().atleast_version("1.0.0").find("openssl") {
-        build_old_openssl_shim(false, info.include_paths);
+        build_old_openssl_shim(vec![]);
         return;
     }
 
     let err = match pkg_config::find_library("openssl") {
         Ok(info) => {
-            build_old_openssl_shim(true, info.include_paths);
+            build_old_openssl_shim(info.include_paths);
             return;
         }
         Err(err) => err,
@@ -40,23 +34,19 @@ fn main() {
     // pkg-config doesn't know of OpenSSL on FreeBSD 10.1 and OpenBSD uses LibreSSL
     if target.contains("bsd") {
         println!("cargo:rustc-flags=-l crypto -l ssl");
-        // going to assume the base system includes a new version of openssl
-        build_old_openssl_shim(false, vec![]);
+        build_old_openssl_shim(vec![]);
         return;
     }
 
     panic!("unable to find openssl: {}", err);
 }
 
-fn build_old_openssl_shim(is_old: bool, include_paths: Vec<Path>) {
+fn build_old_openssl_shim(include_paths: Vec<Path>) {
     let mut config = gcc::Config::new();
 
     for path in include_paths {
         config.include(path);
     }
-    if is_old {
-        config.define("OLD_OPENSSL", None);
-    }
 
     config.file("src/old_openssl_shim.c")
         .compile("libold_openssl_shim.a");
diff --git a/openssl-sys/src/old_openssl_shim.c b/openssl-sys/src/old_openssl_shim.c
index 473bd2ae..19ce74fc 100644
--- a/openssl-sys/src/old_openssl_shim.c
+++ b/openssl-sys/src/old_openssl_shim.c
@@ -1,6 +1,6 @@
 #include <openssl/hmac.h>
 
-#ifdef OLD_OPENSSL
+#if OPENSSL_VERSION_NUMBER < 0x1000000L
 // Copied from openssl crypto/hmac/hmac.c
 int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
      {
@@ -33,7 +33,7 @@ int HMAC_Final_shim(HMAC_CTX *ctx, unsigned char *md, unsigned int *len) {
     return 1;
 }
 
-#else /* OLD_OPENSSL */
+#else
 
 int HMAC_Init_ex_shim(HMAC_CTX *ctx, const void *key, int key_len, const EVP_MD *md, ENGINE *impl) {
     return HMAC_Init_ex(ctx, key, key_len, md, impl);
@@ -46,4 +46,4 @@ int HMAC_Update_shim(HMAC_CTX *ctx, const unsigned char *data, int len) {
 int HMAC_Final_shim(HMAC_CTX *ctx, unsigned char *md, unsigned int *len) {
     return HMAC_Final(ctx, md, len);
 }
-#endif /* OLD_OPENSSL */
+#endif