Allow to specify custom path for Perl (#49)

* Allow to specify custom path for Perl

Env var OPENSSL_SRC_PERL can be set to specify
a path to the perl binary to use to call the openssl
perl scripts.

Resolves #45

* Fallback to PERL env var if OPENSSL_SRC_PERL is not set

Author: D4nte

.github/workflows/main.yml

@@ -122,7 +122,7 @@ jobs:
       shell: bash
     - name: Use strawberry perl
       if: startsWith(matrix.os, 'windows')
-      run: echo ::add-path::C:/Strawberry/perl/bin
+      run: echo ::set-env name=OPENSSL_SRC_PERL::C:/Strawberry/perl/bin/perl
       shell: bash
     - run: |
         set -e

src/lib.rs

@@ -77,7 +77,9 @@ impl Build {
         cp_r(&source_dir(), &inner_dir);
         apply_patches(target, &inner_dir);
 
-        let mut configure = Command::new("perl");
+        let perl_program =
+            env::var("OPENSSL_SRC_PERL").unwrap_or(env::var("PERL").unwrap_or("perl".to_string()));
+        let mut configure = Command::new(perl_program);
         configure.arg("./Configure");
         if host.contains("pc-windows-gnu") {
             configure.arg(&format!("--prefix={}", sanitize_sh(&install_dir)));