$OpenBSD: patch-Source_cmTarget_cxx,v 1.16 2012/11/15 08:43:25 dcoppa Exp $
--- Source/cmTarget.cxx.orig	Tue Nov  6 20:41:36 2012
+++ Source/cmTarget.cxx	Mon Nov 12 12:14:34 2012
@@ -3097,12 +3097,16 @@ std::string cmTarget::GetPDBName(const char* config)
 //----------------------------------------------------------------------------
 bool cmTarget::HasSOName(const char* config)
 {
+#if !defined(__OpenBSD__)
   // soname is supported only for shared libraries and modules,
   // and then only when the platform supports an soname flag.
   return ((this->GetType() == cmTarget::SHARED_LIBRARY ||
            this->GetType() == cmTarget::MODULE_LIBRARY) &&
           !this->GetPropertyAsBool("NO_SONAME") &&
           this->Makefile->GetSONameFlag(this->GetLinkerLanguage(config)));
+#else
+  return false;
+#endif
 }
 
 //----------------------------------------------------------------------------
@@ -3455,9 +3459,43 @@ void cmTarget::GetLibraryNames(std::string& name,
   // The library name.
   name = 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 && strlen(env_vers_cstr) > 0) {
+      // 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 {
+        version = env_vers_cstr;
+      }
+    }
+  }
+
   // The library's soname.
   this->ComputeVersionedName(soName, prefix, base, suffix,
+                             name, version);
+#else
+  // The library's soname.
+  this->ComputeVersionedName(soName, prefix, base, suffix,
                              name, soversion);
+#endif
 
   // The library's real name on disk.
   this->ComputeVersionedName(realName, prefix, base, suffix,
@@ -3490,7 +3528,23 @@ void cmTarget::ComputeVersionedName(std::string& vName
   if(version)
     {
     vName += ".";
+#if defined(__OpenBSD__)
+    // OpenBSD-style versioning 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;
+        }
+      vName += version[i];
+      }
+#else
     vName += version;
+#endif
     }
   vName += this->IsApple? suffix : std::string();
 }