Fix a few issues found by code analysis

Author: mgreter

src/ast_callables.cpp

@@ -124,7 +124,8 @@ namespace Sass {
     Callable(SourceSpan::internal("[EXTERNAL]")),
     envkey_(fname),
     declaration_(parameters),
-    lambda_(lambda)
+    lambda_(lambda),
+    cookie_(nullptr)
   {}
 
   // Equality comparator (needed for `get-function` value)

src/ast_imports.hpp

@@ -54,12 +54,7 @@ namespace Sass {
   // They also don't allow any supports or media queries.
   class IncludeImport final : public ImportBase, public ModRule
   {
-  private:
-    ADD_PROPERTY(bool, wasExported33);
   public:
-
-    const sass::vector<ResolvedImport>* candidates22 = nullptr;
-
     IncludeImport(const SourceSpan& pstate,
       const sass::string& prev,
       const sass::string& url,

src/ast_nodes.hpp

@@ -196,13 +196,15 @@ namespace Sass {
   public:
 
     // Value copy constructor
-    Statement(const SourceSpan& pstate)
-      : AstNode(pstate)
+    Statement(const SourceSpan& pstate) :
+      AstNode(pstate),
+      tabs_(0)
     {}
 
     // Value move constructor
-    Statement(SourceSpan&& pstate)
-      : AstNode(std::move(pstate))
+    Statement(SourceSpan&& pstate) :
+      AstNode(std::move(pstate)),
+      tabs_(0)
     {}
 
     // Copy constructor

src/parser_stylesheet.cpp

@@ -304,7 +304,7 @@ namespace Sass {
     if (isIndented() && styles->empty()) {
       compiler.addWarning(
         "This selector doesn't have any properties and won't be rendered.",
-        itpl->pstate());
+        itpl ? itpl->pstate() : SourceSpan{});
     }
 
     return styles.detach();

src/source_map.cpp

@@ -96,7 +96,7 @@ namespace Sass {
   {
     if (out.srcmap) {
       Offset size(out.srcmap->position);
-      for (Mapping mapping : out.srcmap->mappings) {
+      for (const Mapping& mapping : out.srcmap->mappings) {
         if (mapping.target.line > size.line) {
           throw(std::runtime_error("prepend sourcemap has illegal line"));
         }