[Buildroot] question on config.cache

[Ben Kloosterman]

Im trying to crosscompile mono on i386 + uclib (without mmu)  and have
created a package and after a few things I fixed I now get stuck on 

"checking for preceding underscore symbols"    then the cannot run prog
message. 

I found you should/can set the mono_cv_sizeof_sunpath  and mono_cv_uscore
config cache options but how exactly do I do this in buildroot  ?  I tried
some echos in the mono.mk file but they were just ignored.  Im using a basic
autoconfig mk file.

Regards, 

Ben Kloosterman