fix realloc when initial size was 0 (bug reported by Jens Mueller)
fix realloc when initial size was 0 (bug reported by Jens Mueller)

ritsu1228/eigen,cjntaylor/eigen,TSC21/Eigen,toastedcrumpets/eigen,pasuka/eigen,Zefz/eigen,ritsu1228/eigen,ritsu1228/eigen,pthulhu/eigen,ROCmSoftwarePlatform/hipeigen,cjntaylor/eigen,toastedcrumpets/eigen,Zefz/eigen,pasuka/eigen,pthulhu/eigen,ROCmSoftwarePlatform/hipeigen,TSC21/Eigen,cjntaylor/eigen,cjntaylor/eigen,ritsu1228/eigen,TSC21/Eigen,pasuka/eigen,ROCmSoftwarePlatform/hipeigen,Zefz/eigen,pthulhu/eigen,toastedcrumpets/eigen,pthulhu/eigen,pasuka/eigen,TSC21/Eigen,toastedcrumpets/eigen,ROCmSoftwarePlatform/hipeigen,pasuka/eigen,ritsu1228/eigen,Zefz/eigen,pthulhu/eigen