MachO::Binary::extend_section fill gap by default

The previous implementation extended section by strictly requested
amount, possibly creating a gap in case we needed to satisfy alignment
requirements.

However, information about the size of the gap is lost, and not trivial
to recover. This patch changes `extend_section` to extend section by
more than requested to avoid creating the gap.

include/LIEF/MachO/Binary.hpp

@@ -411,8 +411,9 @@ class LIEF_API Binary : public LIEF::Binary  {
   bool extend_segment(const SegmentCommand& segment, size_t size);
 
   /// Extend the **content** of the given Section.
-  /// @note This method may create a gap between the current section and the next one, if `size`
-  ///       is not multiple of the maximum alignment of sections before the current one.
+  /// @note This method may extend the section more than `size` preventing creation a gap
+  ///       between the current section and the next one.
+  ///       This may happen trying to satisfy alignment requirement of sections.
   /// @note This method works only with sections that belong to the first segment.
   bool extend_section(Section& section, size_t size);
 

src/MachO/Binary.cpp

@@ -1305,7 +1305,7 @@ bool Binary::extend_section(Section& section, size_t size) {
   }
 
   // Extend the given `section`.
-  section.size(section.size() + size);
+  section.size(section.size() + shift_value);
 
   return true;
 }