community/nodejs-current: prevent rebuild in rootpkg()

builders stuck on second rebuild at rootpkg() probably because newer gcc is used

caused by fresher

• gcc after fbda040c

• binutils after e9003d6e

• node upgrade !25712 (merged)

• fix build

• prevent duplicated usage of common flags

• prevent second re-build at package()

-Os -fomit-frame-pointer -Os -fomit-frame-pointer -c
...
-fomit-frame-pointer -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64  -fomit-frame-pointer -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -c