fix some compilation errors of function luc in zzn.h and zzn.cpp
The patch fixes some compilation errors in building libmiracl.a, tests on Ubuntu 20.04.3 x86_64 with g++ 9.4.0 and sed 4.2.2-8:
zzn.h:186:17: error: friend declaration of ‘ZZn luc(const ZZn&, const Big&, ZZn*)’ specifies default arguments and isn’t a definition, the standard (§8.3.6-4) says that "If a friend declaration specifies a default argument expression, that declaration shall be a definition and shall be the only declaration of the function or function template in the translation unit".
zzn.cpp:170:21: error: no matching function for call to ‘luc(ZZn, const Big&)’, order of luc and powl need to exchange.
The patch fixes some compilation errors in building libmiracl.a, tests on Ubuntu 20.04.3 x86_64 with g++ 9.4.0 and sed 4.2.2-8:
zzn.h:186:17: error: friend declaration of ‘ZZn luc(const ZZn&, const Big&, ZZn*)’ specifies default arguments and isn’t a definition, the standard (§8.3.6-4) says that "If a friend declaration specifies a default argument expression, that declaration shall be a definition and shall be the only declaration of the function or function template in the translation unit".zzn.cpp:170:21: error: no matching function for call to ‘luc(ZZn, const Big&)’, order of luc and powl need to exchange.