$OpenBSD: patch-Source_cmTarget_cxx,v 1.9 2011/09/20 11:32:36 dcoppa Exp $
--- Source/cmTarget.cxx.orig	Fri Jul  8 14:21:47 2011
+++ Source/cmTarget.cxx	Fri Sep  9 09:49:49 2011
@@ -3276,6 +3276,36 @@ void cmTarget::GetLibraryNames(std::string& name,
   std::string suffix;
   this->GetFullNameInternal(config, false, prefix, base, suffix);
 
+#if defined(__OpenBSD__)
+  // Override shared library version using LIBxxx_VERSION 
+  // environment variable. Needed for OpenBSD ports system.
+  if(this->GetType() == cmTarget::SHARED_LIBRARY ||
+     this->GetType() == cmTarget::MODULE_LIBRARY)
+    {
+    std::string env_name = "LIB" + base + "_VERSION";
+    char *env_vers_cstr = getenv(env_name.c_str());
+
+    if (env_vers_cstr != NULL) {
+      // This means an override is present.
+      std::string env_vers = std::string(env_vers_cstr);
+
+      size_t first = env_vers.find_first_of(".");
+      size_t last = env_vers.find_first_of(".");
+
+      if ((first != last) || (first == std::string::npos)) {
+        std::string msg = "Bad ";
+        msg += env_name;
+        msg += " specification: ";
+        msg += env_vers;
+        this->Makefile->IssueMessage(cmake::FATAL_ERROR, 
+                                     msg.c_str());
+      } else {
+        soversion = version = env_vers_cstr;
+      }
+    }
+  }
+#endif
+
   // The library name.
   name = prefix+base+suffix;
 
@@ -3310,8 +3340,27 @@ void cmTarget::GetLibraryNames(std::string& name,
   if(version)
     {
     realName += ".";
+#if defined(__OpenBSD__)
+    // OpenBSD-style versioning scheme for shared libraries.
+    // Convert libname.so.X.X.X to libname.so.X.X
+    int j = 0;
+    for (int i = 0; i < (int)strlen(version); i++) 
+      {
+      if (version[i] == '.') 
+        {
+        j++; 
+        if (j == 2) 
+          {
+          break;
+          }
+        }
+      realName += version[i];
+      }
+    }
+#else
     realName += version;
     }
+#endif
   else if(soversion)
     {
     realName += ".";