build warning on alpine with gcc 10.2.1
[733/1034] Building CXX object alib2algo/CMakeFiles/alib2algo.dir/src/stringology/exact/KnuthMorrisPratt.cpp.o
In file included from ../alib2algo/src/stringology/exact/KnuthMorrisPratt.h:8,
from ../alib2algo/src/stringology/exact/KnuthMorrisPratt.cpp:1:
../alib2algo/src/string/properties/BorderArray.h: In static member function 'static ext::vector<long unsigned int> string::properties::BorderArray::construct(const string::LinearString<SymbolType>&) [with SymbolType = object::Object]':
../alib2algo/src/string/properties/BorderArray.h:26:9: warning: potential null pointer dereference [-Wnull-dereference]
26 | res[0] = -1;