Author: Nathan Phillip Brink <ohnobinki@ohnopublishing.net>
Date: 2010/09/17
Purpose: Add a global FIND_LIBRARY_USE_LIB32_PATHS property which is
        an analog to the existing FIND_LIBRARY_USE_LIB64_PATHS
        property. This fixes kde-base/kdelib's ability to find
        automoc4 using FIND_PACKAGE's NO_MODULE mode on systems where
        /usr/lib is neither a symlink to /usr/lib64 or /usr/lib32.
Gentoo-Bug: 338492

diff --git a/Modules/Platform/UnixPaths.cmake b/Modules/Platform/UnixPaths.cmake
index 5ee7ddb..afcde6f 100644
--- a/Modules/Platform/UnixPaths.cmake
+++ b/Modules/Platform/UnixPaths.cmake
@@ -86,3 +86,6 @@ LIST(APPEND CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES
 
 # Enable use of lib64 search path variants by default.
 SET_PROPERTY(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS TRUE)
+# Enable use of lib32 search path variants by default. Useful on
+# multilib systems. Not harmful for normal systems.
+SET_PROPERTY(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS TRUE)
diff --git a/Source/cmFindLibraryCommand.cxx b/Source/cmFindLibraryCommand.cxx
index 9077c8e..e09967d 100644
--- a/Source/cmFindLibraryCommand.cxx
+++ b/Source/cmFindLibraryCommand.cxx
@@ -92,6 +92,12 @@ bool cmFindLibraryCommand
     // add special 64 bit paths if this is a 64 bit compile.
     this->AddLib64Paths();
     }
+  if(this->Makefile->GetCMakeInstance()
+     ->GetPropertyAsBool("FIND_LIBRARY_USE_LIB32_PATHS"))
+    {
+    // add special 32 bit paths if this is a 32 bit compile.
+    this->AddLib32Paths();
+    }
 
   std::string library = this->FindLibrary();
   if(library != "")
@@ -160,10 +166,7 @@ void cmFindLibraryCommand::AddLib64Paths()
     {
     return;
     }
-  std::string voidsize =
-    this->Makefile->GetSafeDefinition("CMAKE_SIZEOF_VOID_P");
-  int size = atoi(voidsize.c_str());
-  if(size != 8)
+  if(!this->Makefile->PlatformIs64Bit())
     {
     return;
     }
@@ -205,6 +208,55 @@ void cmFindLibraryCommand::AddLib64Paths()
     }
 }
 
+void cmFindLibraryCommand::AddLib32Paths()
+{  
+  if(!this->Makefile->GetLocalGenerator()->GetGlobalGenerator()->
+     GetLanguageEnabled("C"))
+    {
+    return;
+    }
+  if(!this->Makefile->PlatformIs32Bit())
+    {
+    return;
+    }
+  std::vector<std::string> path32;
+  bool found32 = false;
+  for(std::vector<std::string>::iterator i = this->SearchPaths.begin(); 
+      i != this->SearchPaths.end(); ++i)
+    {
+    std::string s = *i;
+    std::string s2 = *i;
+    cmSystemTools::ReplaceString(s, "lib/", "lib32/");
+    // try to replace lib with lib32 and see if it is there,
+    // then prepend it to the path
+    // Note that all paths have trailing slashes.
+    if((s != *i) && cmSystemTools::FileIsDirectory(s.c_str()))
+      {
+      path32.push_back(s);
+      found32 = true;
+      }  
+    // now just add a 32 to the path name and if it is there,
+    // add it to the path
+    s2 += "32/";
+    if(cmSystemTools::FileIsDirectory(s2.c_str()))
+      {
+      found32 = true;
+      path32.push_back(s2);
+      } 
+    // now add the original unchanged path
+    if(cmSystemTools::FileIsDirectory(i->c_str()))
+      {
+      path32.push_back(*i);
+      }
+    }
+  // now replace the SearchPaths with the 32 bit converted path
+  // if any 32 bit paths were discovered
+  if(found32)
+    {
+    this->SearchPaths = path32;
+    }
+}
+
 //----------------------------------------------------------------------------
 std::string cmFindLibraryCommand::FindLibrary()
 {
diff --git a/Source/cmFindLibraryCommand.h b/Source/cmFindLibraryCommand.h
index 486c2cf..e0dd49d 100644
--- a/Source/cmFindLibraryCommand.h
+++ b/Source/cmFindLibraryCommand.h
@@ -63,6 +63,7 @@ public:
 protected:
   void AddArchitecturePaths(const char* suffix);
   void AddLib64Paths();
+  void AddLib32Paths();
   std::string FindLibrary();
 private:
   std::string FindNormalLibrary();
diff --git a/Source/cmFindPackageCommand.cxx b/Source/cmFindPackageCommand.cxx
index ef0197a..b0a2985 100644
--- a/Source/cmFindPackageCommand.cxx
+++ b/Source/cmFindPackageCommand.cxx
@@ -66,6 +66,7 @@ cmFindPackageCommand::cmFindPackageCommand()
   this->NoModule = false;
   this->DebugMode = false;
   this->UseLib64Paths = false;
+  this->UseLib32Paths = false;
   this->PolicyScope = true;
   this->VersionMajor = 0;
   this->VersionMinor = 0;
@@ -341,6 +342,13 @@ bool cmFindPackageCommand
     {
     this->UseLib64Paths = true;
     }
+  // Lookup whether lib32 paths should be used.
+  if(this->Makefile->PlatformIs32Bit() &&
+     this->Makefile->GetCMakeInstance()
+     ->GetPropertyAsBool("FIND_LIBRARY_USE_LIB32_PATHS"))
+    {
+    this->UseLib32Paths = true;
+    }
 
   // Find the current root path mode.
   this->SelectDefaultRootPathMode();
@@ -2105,6 +2113,10 @@ bool cmFindPackageCommand::SearchPrefix(std::string const& prefix_in)
     {
     common.push_back("lib64");
     }
+  if(this->UseLib32Paths)
+    {
+    common.push_back("lib32");
+    }
   common.push_back("lib");
   common.push_back("share");
 
diff --git a/Source/cmFindPackageCommand.h b/Source/cmFindPackageCommand.h
index 57aeab9..06edc1a 100644
--- a/Source/cmFindPackageCommand.h
+++ b/Source/cmFindPackageCommand.h
@@ -134,6 +134,7 @@ private:
   bool NoBuilds;
   bool DebugMode;
   bool UseLib64Paths;
+  bool UseLib32Paths;
   bool PolicyScope;
   std::vector<std::string> Names;
   std::vector<std::string> Configs;
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index c64053a..c6cda07 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -1993,6 +1993,15 @@ bool cmMakefile::PlatformIs64Bit() const
   return false;
 }
 
+bool cmMakefile::PlatformIs32Bit() const
+{
+  if(const char* sizeof_dptr = this->GetDefinition("CMAKE_SIZEOF_VOID_P"))
+    {
+    return atoi(sizeof_dptr) == 4;
+    }
+  return false;
+}
+
 bool cmMakefile::CanIWriteThisFile(const char* fileName)
 {
   if ( !this->IsOn("CMAKE_DISABLE_SOURCE_CHANGES") )
diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index 8b8a3f8..c16ba71 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -588,6 +588,8 @@ public:
 
   /** Return whether the target platform is 64-bit.  */
   bool PlatformIs64Bit() const;
+  /** Return whether the target platform is 32-bit. */
+  bool PlatformIs32Bit() const;
 
   /**
    * Get a list of preprocessor define flags.
diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index 1e3b018..2bc3eba 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -3365,6 +3365,13 @@ void cmake::DefineProperties(cmake *cm)
      "directories called lib in the search path when building 64-bit "
      "binaries.");
   cm->DefineProperty
+    ("FIND_LIBRARY_USE_LIB32_PATHS", cmProperty::GLOBAL,
+     "Whether FIND_LIBRARY should automatically search lib32 directories.",
+     "FIND_LIBRARY_USE_LIB32_PATHS is a boolean specifying whether the"
+     " FIND_LIBRARY command should automatically search the lib32 variant of"
+     " directories called lib in the search path when building 32-bit"
+     " binaries.");
+  cm->DefineProperty
     ("FIND_LIBRARY_USE_OPENBSD_VERSIONING", cmProperty::GLOBAL,
      "Whether FIND_LIBRARY should find OpenBSD-style shared libraries.",
      "This property is a boolean specifying whether the FIND_LIBRARY "