(maint) Recreate ability to pass in OPENSSL_LIBS variable

Prior to this commit in 43c951f743e68fac5f45119eda7c994882a1d489 the
ability to pass OPENSSL_LIBS was removed from the build.rs of
openssl-sys. This commit adds the ability to pass custom names for the
OPENSSL_LIBS back in. This is useful for when building openssl across
linux and windows with the same lib names (ssl:crypto) and the default
names provided by the build script are not valid.

1 files changed, 13 insertions, 6 deletions

diff --git a/openssl-sys/build.rs b/openssl-sys/build.rs
index fc0f4680..969c5983 100644
--- a/openssl-sys/build.rs
+++ b/openssl-sys/build.rs
@@ -65,16 +65,23 @@ fn main() {
 
     let version = validate_headers(&[include_dir.clone().into()]);
 
-    let libs = match version {
-        Version::Openssl101 | Version::Openssl102 if target.contains("windows") => {
-            ["ssleay32", "libeay32"]
+    let libs_env = env::var("OPENSSL_LIBS").ok();
+    let libs = match libs_env {
+        Some(ref v) => v.split(":").collect(),
+        None => {
+            match version {
+                Version::Openssl101 | Version::Openssl102 if target.contains("windows") => {
+                    vec!["ssleay32", "libeay32"]
+                }
+                Version::Openssl110 if target.contains("windows") => vec!["libssl", "libcrypto"],
+                _ => vec!["ssl", "crypto"],
+            }
         }
-        Version::Openssl110 if target.contains("windows") => ["libssl", "libcrypto"],
-        _ => ["ssl", "crypto"],
     };
 
+
     let kind = determine_mode(Path::new(&lib_dir), &libs);
-    for lib in libs.iter() {
+    for lib in libs.into_iter() {
         println!("cargo:rustc-link-lib={}={}", kind, lib);
     }
 }