Test for curve25519-donna-c64 is broken when cross compiling
In #8587 (moved), the test for curve25519-donna-c64 was improved, but it doesn't work as expected when cross compiling. I'm cross compiling for armv7 and the test does not fail to compile, as current behavior expects it to. It fails to link, however, finding "___multi3" (128-bit multiply) to be an undefined symbol.
I attached a small patch that should fix this.