• Add failing tests; SVt_RV is not directly SvROK [gfx]
  
• Implement openhandle() in XS (with extra tests) [gfx]
  
• Modernize *.pm [gfx]
  
• Modernize ListUtil.xs [gfx]
  
• Add ppport.h [gfx]
  
• Fix an overloading issue on sum(), and add tests for overloading [gfx]
  
• Small tweaks for minstr()/maxstr() [gfx]
  
• Optimize dualvar() [gfx]
  
• Use sv_copypv() instead of SvPV() and sv_setpv() [gfx]
  
• avoid non-portable warnings