Hi,

Thank you for your bug report.

I do not see that Libtool supports ml64, the Microsoft Macro Assembler.
The error you received is for not using the --tag option. Since there
are different configurations for the different tags, it is important to
specify the intended configuration. However, an unsupported compiler
could be used with a supported tag, which would lead to issues with
object and library creation. I will work on a fix for this bug, but this
commit [1] should help users understand tagging better.

Since ml64 is unsupported, I suggest recreating the file in C, and then,
the C compiler could be used to generate an assembly file to link within
a library. However, it would be better to add assembly compilation to
Libtool.

[1] 
https://git.savannah.gnu.org/cgit/libtool.git/commit/?h=development&id=376411905b3f479b52c69a8a62f258b6ba62fc01

-- 
Ileana Dumitrescu

GPG Public Key: FA26 CA78 4BE1 8892 7F22 B99F 6570 EA01 146F 7354