Adjust linker_is_gnu branches for cases that don't work on windows.
Adjust linker_is_gnu branches for cases that don't work on windows.

aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust