Clean up header includes

1. Avoid include cycles. This isn't necessary for amalgamation but makes
   things more obvious.

2. Rename sass2scss namespace to Sass2Scss (upstream PR
   mgreter/sass2scss#43).

   This is necessary for amalgamation.

Author: glebm

include/sass2scss.h

@@ -41,7 +41,7 @@
 #endif
 
 // add namespace for c++
-namespace Sass
+namespace Sass2Scss
 {
 
 	// pretty print options
@@ -117,4 +117,4 @@ extern "C" {
 } // __cplusplus defined.
 #endif
 
-#endif
+#endif

src/ast.cpp

@@ -3,6 +3,11 @@
 #include "sass.hpp"
 
 #include "ast.hpp"
+#include "ast_selectors.hpp"
+#include "ast_values.hpp"
+#include "emitter.hpp"
+#include "inspect.hpp"
+#include "util.hpp"
 
 namespace Sass {
 

src/ast.hpp

@@ -1052,10 +1052,6 @@ namespace Sass {
 
 }
 
-#include "ast_values.hpp"
-#include "ast_supports.hpp"
-#include "ast_selectors.hpp"
-
 #ifdef __clang__
 
 // #pragma clang diagnostic pop

src/ast2c.cpp

@@ -4,6 +4,9 @@
 
 #include "ast2c.hpp"
 #include "ast.hpp"
+#include "ast_selectors.hpp"
+#include "ast_supports.hpp"
+#include "ast_values.hpp"
 
 namespace Sass {
 
@@ -77,4 +80,7 @@ namespace Sass {
   union Sass_Value* AST2C::operator()(Null* n)
   { return sass_make_null(); }
 
+  union Sass_Value* AST2C::fallback(AST_Node* x)
+  { return sass_make_error("unknown type for C-API"); }
+
 };

src/ast2c.hpp

@@ -29,9 +29,7 @@ namespace Sass {
     union Sass_Value* operator()(Argument*);
 
     // return sass error if type is not supported
-    union Sass_Value* fallback(AST_Node* x)
-    { return sass_make_error("unknown type for C-API"); }
-
+    union Sass_Value* fallback(AST_Node* x);
   };
 
 }

src/ast_fwd_decl.cpp

@@ -1,5 +1,9 @@
 #include "ast.hpp"
 
+#include "ast_selectors.hpp"
+#include "ast_supports.hpp"
+#include "ast_values.hpp"
+
 namespace Sass {
 
   #define IMPLEMENT_BASE_CAST(T) \

src/ast_sel_cmp.cpp

@@ -2,7 +2,10 @@
 // __EXTENSIONS__ fix on Solaris.
 #include "sass.hpp"
 
+#include <unordered_set>
+
 #include "ast_selectors.hpp"
+#include "ast_values.hpp"
 
 namespace Sass {
 

src/ast_sel_super.cpp

@@ -2,7 +2,8 @@
 // __EXTENSIONS__ fix on Solaris.
 #include "sass.hpp"
 #include "ast.hpp"
-
+#include "ast_selectors.hpp"
+#include "ast_values.hpp"
 #include "util_string.hpp"
 
 namespace Sass {
@@ -76,7 +77,7 @@ namespace Sass {
           // That items must be a compound selector
           if (auto compound = Cast<CompoundSelector>(complex->at(0))) {
             // It must contain the lhs simple selector
-            if (!compound->contains(simple1)) { 
+            if (!compound->contains(simple1)) {
               return false;
             }
           }
@@ -386,8 +387,8 @@ namespace Sass {
 
       // Find the first index where `complex2.sublist(i2, afterSuperselector)`
       // is a subselector of [compound1]. We stop before the superselector
-      // would encompass all of [complex2] because we know [complex1] has 
-      // more than one element, and consuming all of [complex2] wouldn't 
+      // would encompass all of [complex2] because we know [complex1] has
+      // more than one element, and consuming all of [complex2] wouldn't
       // leave anything for the rest of [complex1] to match.
       size_t afterSuperselector = i2 + 1;
       for (; afterSuperselector < complex2.size(); afterSuperselector++) {

src/ast_sel_unify.cpp

@@ -4,10 +4,13 @@
 
 #include "ast.hpp"
 
+#include "ast_selectors.hpp"
+#include "util.hpp"
+
 namespace Sass {
 
   // ##########################################################################
-  // Returns the contents of a [SelectorList] that matches only 
+  // Returns the contents of a [SelectorList] that matches only
   // elements that are matched by both [complex1] and [complex2].
   // If no such list can be produced, returns `null`.
   // ##########################################################################

src/ast_sel_weave.cpp

@@ -3,6 +3,7 @@
 #include "sass.hpp"
 
 #include "ast.hpp"
+#include "ast_selectors.hpp"
 #include "permutate.hpp"
 #include "dart_helpers.hpp"
 
@@ -190,7 +191,7 @@ namespace Sass {
   // EO getChunks
 
   // ##########################################################################
-  // If the first element of [queue] has a `::root` 
+  // If the first element of [queue] has a `::root`
   // selector, removes and returns that element.
   // ##########################################################################
   CompoundSelectorObj getFirstIfRoot(std::vector<SelectorComponentObj>& queue) {
@@ -298,7 +299,7 @@ namespace Sass {
         return true;
       }
     }
-    
+
     std::vector<SelectorComponentObj> combinators1;
     while (!components1.empty() && Cast<SelectorCombinator>(components1.back())) {
       SelectorCombinatorObj back = Cast<SelectorCombinator>(components1.back());
@@ -379,7 +380,7 @@ namespace Sass {
         else {
           CompoundSelectorObj unified = compound1->unifyWith(compound2);
           std::vector<std::vector<SelectorComponentObj>> items;
-          
+
           if (!unified.isNull()) {
             items.push_back({
               unified, nextSiblingCombinator