Fix minor Coverity warnings and minor compil warnings.

(uninitialized or shadowed vars)

include/settings/environment.h

@@ -61,6 +61,7 @@ class ENV_VAR_ITEM
 public:
     ENV_VAR_ITEM( const wxString& aValue = wxEmptyString, bool aIsDefinedExternally = false ) :
             m_value( aValue ),
+            m_isBuiltin( true ),
             m_isDefinedExternally( aIsDefinedExternally ),
             m_isDefinedInSettings( false )
     {

kicad/kicad.cpp

@@ -341,8 +341,10 @@ struct APP_KICAD : public wxApp
             wxKeyEvent* keyEvent = static_cast<wxKeyEvent*>( &aEvent );
 
             if( keyEvent )
+            {
                 wxLogTrace( kicadTraceKeyEvent, "APP_KICAD::ProcessEvent %s", dump( *keyEvent ) );
             }
+        }
 
         aEvent.Skip();
         return false;

pcbnew/dimension.cpp

@@ -968,7 +968,8 @@ void LEADER::updateGeometry()
 
     SEG arrowSeg( m_start, m_end );
     SEG textSeg( m_end, m_text.GetPosition() );
-    OPT_VECTOR2I arrowSegEnd, textSegEnd;
+    OPT_VECTOR2I arrowSegEnd = boost::make_optional( false, VECTOR2I() );;
+    OPT_VECTOR2I textSegEnd = boost::make_optional( false, VECTOR2I() );
 
     if( m_textFrame == DIM_TEXT_FRAME::CIRCLE )
     {

pcbnew/drc/drc_engine.cpp

@@ -303,10 +303,10 @@ void DRC_ENGINE::loadImplicitRules()
                     netclassRule->m_Condition = new DRC_RULE_CONDITION( expr );
                     netclassItemSpecificRules.push_back( netclassRule );
 
-                    DRC_CONSTRAINT clearanceConstraint( CLEARANCE_CONSTRAINT );
-                    clearanceConstraint.Value().SetMin( std::max( bds.m_MinClearance,
+                    DRC_CONSTRAINT min_clearanceConstraint( CLEARANCE_CONSTRAINT );
+                    min_clearanceConstraint.Value().SetMin( std::max( bds.m_MinClearance,
                                                                   nc->GetDiffPairGap() ) );
-                    netclassRule->AddConstraint( clearanceConstraint );
+                    netclassRule->AddConstraint( min_clearanceConstraint );
                 }
 
                 if( nc->GetViaDiameter() || nc->GetViaDrill() )