Compilation error with GCC 6.1.1

When I try to compile the urbackup-client on linux using GCC 6.1.1 (x86_64 GNU/Linux) it fails with the following error.
Any idea what’s going wrong?

make[2]: Entering directory ‘/home/i/Downloads/urbackup-client-1.4.11’
g++ -DHAVE_CONFIG_H -I. -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -pthread -DLINUX -g -O2 -MT stringtools.o -MD -MP -MF .deps/stringtools.Tpo -c -o stringtools.o stringtools.cpp
stringtools.cpp: In function ‘bool IsHex(const string&)’:
stringtools.cpp:1250:17: error: missing template arguments before ‘[’ token
if(std::array[t]==str[i])
^
stringtools.cpp: In function ‘long unsigned int hexToULong(const string&)’:
stringtools.cpp:1274:18: error: reference to ‘array’ is ambiguous
if( str[i] == array[j])
^~~~~
stringtools.cpp:1240:12: note: candidates are: const char array [16]
const char array[] = {‘0’,‘1’,‘2’,‘3’,‘4’,‘5’,‘6’,‘7’,‘8’,‘9’,‘a’,‘b’,‘c’,‘d’,‘e’,‘f’};
^~~~~
In file included from /usr/include/c++/6.1.1/tuple:39:0,
from /usr/include/c++/6.1.1/bits/stl_map.h:63,
from /usr/include/c++/6.1.1/map:61,
from stringtools.cpp:25:
/usr/include/c++/6.1.1/array:90:12: note: template<class _Tp, long unsigned int _Nm> struct std::array
struct array
^~~~~
stringtools.cpp: In function ‘std::__cxx11::string byteToHex(unsigned char)’:
stringtools.cpp:1287:7: error: reference to ‘array’ is ambiguous
r[0]=array[ch%16];
^~~~~
stringtools.cpp:1240:12: note: candidates are: const char array [16]
const char array[] = {‘0’,‘1’,‘2’,‘3’,‘4’,‘5’,‘6’,‘7’,‘8’,‘9’,‘a’,‘b’,‘c’,‘d’,‘e’,‘f’};
^~~~~
In file included from /usr/include/c++/6.1.1/tuple:39:0,
from /usr/include/c++/6.1.1/bits/stl_map.h:63,
from /usr/include/c++/6.1.1/map:61,
from stringtools.cpp:25:
/usr/include/c++/6.1.1/array:90:12: note: template<class _Tp, long unsigned int _Nm> struct std::array
struct array
^~~~~
stringtools.cpp:1289:7: error: reference to ‘array’ is ambiguous
r[1]=array[ch%16];
^~~~~
stringtools.cpp:1240:12: note: candidates are: const char array [16]
const char array[] = {‘0’,‘1’,‘2’,‘3’,‘4’,‘5’,‘6’,‘7’,‘8’,‘9’,‘a’,‘b’,‘c’,‘d’,‘e’,‘f’};
^~~~~
In file included from /usr/include/c++/6.1.1/tuple:39:0,
from /usr/include/c++/6.1.1/bits/stl_map.h:63,
from /usr/include/c++/6.1.1/map:61,
from stringtools.cpp:25:
/usr/include/c++/6.1.1/array:90:12: note: template<class _Tp, long unsigned int _Nm> struct std::array
struct array
^~~~~
Makefile:647: recipe for target ‘stringtools.o’ failed
make[2]: *** [stringtools.o] Error 1
make[2]: Leaving directory ‘/home/i/Downloads/urbackup-client-1.4.11’
Makefile:681: recipe for target ‘all-recursive’ failed
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory ‘/home/i/Downloads/urbackup-client-1.4.11’
Makefile:424: recipe for target ‘all’ failed
make: *** [all] Error 2