[Makefile] Use EXPORT_CC for make crystal

[straight-shoota]

All recipes use the EXPORT_CC override to configure using lld as linker, except for make crystal. Apparently, that's rarely an issue. But I recently started seeing linking errors like the ones in #7177 with default ld. Using lld fixes that, as we're already doing for all other build targets. This patch usees EXPORT_CC for make crystal as well (via EXPORTS_BUILD).

[straight-shoota]

I considered refactoring this entirely as proposed in #8641 (comment) but I decided to make that a separate change. I'm not sure yet if there should be an option to override adding -fuse=ld.lld to CC (which is currently possible by defining EXPORT_CC).

[zw963]

@straight-shoota , hi, can we add example here for how use ld.ldd as linker when run make in linux?

There is a issue #12542 probably related to this.

[straight-shoota]

Hm, the makefile automatically uses ld.ldd if it's available.