rust: Respect HOSTCC when linking for host

Currently, rustc defaults to invoking `cc`, even if `HOSTCC` is defined,
resulting in build failures in hermetic environments where `cc` does not
exist. This includes both hostprogs and proc-macros.

Since we are setting the linker to `HOSTCC`, we set the linker flavor to
`gcc` explicitly. The linker-flavor selects both which linker to search
for if the linker is unset, and which kind of linker flags to pass.
Without this flag, `rustc` would attempt to determine which flags to
pass based on the name of the binary passed as `HOSTCC`. `gcc` is the
name of the linker-flavor used by `rustc` for all C compilers, including
both `gcc` and `clang`.

Signed-off-by: Matthew Maurer <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Tested-by: Alice Ryhl <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Acked-by: Miguel Ojeda <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>

0 files changed, 0 insertions, 0 deletions