MFH: r545744

sysutils/htop: Fix build with -fno-common

Fix the build of sysutils/htop with -fno-common, which is the default in
llvm 11 (and gcc 10)

PR: 248823
Submitted by: Yasuhiro KIMURA

Approved by: ports-secteam (joenum, implicit, -fno-common fixes)