[Help-gsl] Need help specifying build/host/target to configure

[Michael G Soyka]

Hello.

I'm trying to get GSL 1.8 setup to run on a PowerPC single board 
computer and have not been able to get configure to create either usable 
Makefiles or Makefiles that create PowerPC object files.  I've reviewed 
the GNU Standards file that describes configure (Chapter 7.1) but still 
have questions.

First, some background.  I need to build the GSL to run on a single 
board computer from Mercury Computer Systems.  The processor is a 
PowerPC 750.  It runs an OS called "MCOS".  The OS and hardware are a 
good ten years old.  My development host has a SPARC processor and runs 
Solaris 2.7.  This is where the cross-compiler and related tools are 
installed. 

Question 1.
The configure script takes 3 arguments that appear to be relevant: 
"--build", "--host", and "--target".  Although the GNU Standards file 
talks about them, I'm still unclear as to which ones I should use.  
Could someone please explain the differences between them.  I have tried:

   --build=sparc-sun-solaris2.7
   --host=sparc-sun-solaris2.7
   --target=ppc-ibm-mcos

Forgive me for not being precise about what goes wrong, I don't have 
notes in front of me.  But, as I recall, if I specify all 3, configure 
complains and if I remove "--build", the Makefiles build Solaris object 
files using gcc.  I ran out of time on Friday so could not try other 
combinations. 

Question 2.
What are these .lo and .la files created by the Makefiles?  The reason I 
ask is that my Makefiles contain make variables whose values are of the form

   strdup.oppc$U.oppc

I know something of sed and make and shells but could not fathom what 
the "$U" is supposed to be or why the file extension is replicated. 

Question 3.
What does "libtool" do?


Explanations, links to explanations, advice, etc will be appreciated.  
Thanks in advance.

Mike