net/norm: fix build with clang 16
Since clang 16 (and gcc 11) the default C++ standard is now gnu++17.
Because net/norm's build system does not explicitly set the C++
standard, this leads to several errors:
../src/common/normEncoderRS8.cpp:264:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
USE_GF_MULC ;
^
../src/common/normEncoderRS8.cpp:136:21: note: expanded from macro 'USE_GF_MULC'
#define USE_GF_MULC register gf * __gf_mulc_
^
../src/common/normEncoderRS8.cpp:265:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register gf* dst = dst1;
^~~~~~~~~
../src/common/normEncoderRS8.cpp:266:5: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
register gf* src = src1 ;
^~~~~~~~~Add USE_CXXSTD=gnu++98 to compile for C++98 with GNU extensions instead,
as net/norm does not seem to use any C++11 or later constructs.
PR: 271415
Approved by: portmgr (build fix blanket)
MFH: 2023Q2