Supporting bin_compat option

src/Composer/Installer/LibraryInstaller.php

@@ -34,6 +34,7 @@ class LibraryInstaller implements InstallerInterface
     protected $io;
     protected $type;
     protected $filesystem;
+    protected $binCompat;
 
     /**
      * Initializes library installer.
@@ -53,6 +54,7 @@ class LibraryInstaller implements InstallerInterface
         $this->filesystem = $filesystem ?: new Filesystem();
         $this->vendorDir = rtrim($composer->getConfig()->get('vendor-dir'), '/');
         $this->binDir = rtrim($composer->getConfig()->get('bin-dir'), '/');
+        $this->binCompat = trim(getenv("COMPOSER_BIN_COMPAT")) ?: 'auto';
     }
 
     /**
@@ -219,10 +221,26 @@ class LibraryInstaller implements InstallerInterface
                 $this->io->write('    Skipped installation of bin '.$bin.' for package '.$package->getName().': name conflicts with an existing file');
                 continue;
             }
+            if ($this->binCompat === "auto") {
                 if (defined('PHP_WINDOWS_VERSION_BUILD')) {
+                    $this->installFullBinaries($binPath, $link, $bin, $package);
+                } else {
+                    $this->installSymlinkBinaries($binPath, $link);
+                }
+            } elseif($this->binCompat === "nosymlink") {
+                $this->installUnixyProxyBinaries($binPath, $link);
+            } elseif($this->binCompat === "full") {
+                $this->installFullBinaries($binPath, $link, $bin, $package);
+            }
+            @chmod($link, 0777 & ~umask());
+        }
+    }
+
+    protected function installFullBinaries($binPath, $link, $bin, PackageInterface $package)
+    {
         // add unixy support for cygwin and similar environments
         if ('.bat' !== substr($binPath, -4)) {
-                    file_put_contents($link, $this->generateUnixyProxyCode($binPath, $link));
+            $this->installUnixyProxyBinaries($binPath, $link);
             @chmod($link, 0777 & ~umask());
             $link .= '.bat';
             if (file_exists($link)) {
@@ -232,7 +250,10 @@ class LibraryInstaller implements InstallerInterface
         if (!file_exists($link)) {
             file_put_contents($link, $this->generateWindowsProxyCode($binPath, $link));
         }
-            } else {
+    }
+
+    protected function installSymlinkBinaries($binPath, $link)
+    {
         $cwd = getcwd();
         try {
             // under linux symlinks are not always supported for example
@@ -243,12 +264,14 @@ class LibraryInstaller implements InstallerInterface
                 throw new \ErrorException();
             }
         } catch (\ErrorException $e) {
-                    file_put_contents($link, $this->generateUnixyProxyCode($binPath, $link));
+           $this->installUnixyProxyBinaries($binPath, $link);
         }
         chdir($cwd);
     }
-            @chmod($link, 0777 & ~umask());
-        }
+
+    protected function installUnixyProxyBinaries($binPath, $link)
+    {
+        file_put_contents($link, $this->generateUnixyProxyCode($binPath, $link));
     }
 
     protected function removeBinaries(PackageInterface $package)