using slackware linux x64...
i see 6502 includes for fasmg, but they dont work in fasm 1.71.
are there any 6502.inc for x64 linux?

is there a x64 linux version of fasmg?

The macros written for fasmg are not going to work with fasm 1, fasmg is a new engine with many new or altered features.

As for the x64 versions, neither fasm or fasmg really have one, the "x64" version of fasm 1 is obtained through a trick that allows it to run in long mode while still being basically 32-bit. This variant was made for the rare cases when a Linux system would not be able to execute standard 32-bit executables, but this should be a rare occurrence, normally you should be able to run classic 32-bit executables on x64 system anyway.

The same trick that was used to run fasm 1 in long mode cannot be easily applied to fasmg, because fasmg needs a 32-bit "malloc" API. You need a "multilib" option in order to run it on x64 Linux.