sysutils/htop: fix build on GCC architectures

freebsd/FreeBSDProcessList.c: In function 'FreeBSDProcessList_readJailName':
freebsd/FreeBSDProcessList.c:422: error: #pragma GCC diagnostic not allowed inside functions
freebsd/FreeBSDProcessList.c:422: error: #pragma GCC diagnostic not allowed inside functions
freebsd/FreeBSDProcessList.c:425: warning: cast discards qualifiers from pointer target type
freebsd/FreeBSDProcessList.c:435: error: #pragma GCC diagnostic not allowed inside functions

MFH: 2021Q1