Re: cross compiling gsl for arm cortex M4 (nrf52)

[Mark Galassi]

> [...] those are not include but rather
> missing src file errors, e.g. undefined reference to `gsl_rng_get’ 

You don't give a transcript of the error (hint...), so I'm not sure, but here 
are some thoughts:

1. You got farther than before, since now you have a link error instead of a 
compile error.

2. You have -I stuff in LDFLAGS, which doesn't do anything - you'd want -L 
instead, something like -L/crosscompilearea/gsl-2.7.1/lib/otherlibprefixes

3. I would recommend using LIBRARY_PATH instead, and having in there the full 
path to where you have the libgslsomething.so and libgslsomething.a files.

4. Apart from having a not-belonging -I option in LDFLAGS (it should be in 
CFLAGS and CXXFLAGS), you also seem to have put unneeded quotes, and the first 
of them is a non-ascii double quote.  I don't know if this causes confusion, 
but it might.

Write to me privately and we can have a phone call or share screens in a jitsi 
call.