font_engine : use FT_New_Library/FT_Done_Library with custom memor

management, ref https://github.com/mapnik/mapnik/pull/2241

src/font_engine_freetype.cpp

@@ -37,22 +37,40 @@
 #include <sstream>
 #include <fstream>
 #include <iostream>
+#include <cstdlib>
+
+void* _Alloc_Func(FT_Memory memory, long size) {
+    return std::malloc(size);
+}
+
+void _Free_Func(FT_Memory memory, void *block) {
+    std::free(block);
+}
+
+void* _Realloc_Func(FT_Memory memory, long cur_size, long new_size, void *block) {
+    return std::realloc(block, new_size);
+}
 
 namespace fontserver {
 
 freetype_engine::freetype_engine() :
-    library_(nullptr) {
+    library_(nullptr),
+    memory_(new FT_MemoryRec_) {
 
-    FT_Error error = FT_Init_FreeType(&library_);
+    memory_->alloc = _Alloc_Func;
+    memory_->free = _Free_Func;
+    memory_->realloc = _Realloc_Func;
+    FT_Error error = FT_New_Library( &*memory_, &library_);
     if (error) {
         std::ostringstream runtime_error;
         runtime_error << "Could not load FreeType2 library: FT_Error " << error;
         throw std::runtime_error(runtime_error.str());
     }
+    FT_Add_Default_Modules(library_);
 }
 
 freetype_engine::~freetype_engine() {
-    FT_Done_FreeType(library_);
+    FT_Done_Library(library_);
 }
 
 bool freetype_engine::is_font_file(std::string const& file_name) {

src/font_engine_freetype.hpp

@@ -38,9 +38,11 @@ extern "C"
 #include <ft2build.h>
 #include FT_FREETYPE_H
 // #include FT_STROKER_H
+#include FT_MODULE_H
 }
 
 struct FT_LibraryRec_;
+struct FT_MemoryRec_;
 
 namespace fontserver {
 
@@ -75,6 +77,8 @@ public:
     face_ptr create_face(std::string const& family_name);
 private:
     FT_LibraryRec_ *library_;
+    std::unique_ptr<FT_MemoryRec_> memory_;
+
     static std::mutex mutex_;
     static std::map<std::string, std::pair<int, std::string>> name2file_;
     static std::map<std::string, std::string> memory_fonts_;