[RFA] Use full path for system compiler, not just the first word.

[Klee Dienes]

When building the gcc source tree, gcc passes down a rather convoluted 
compile-command for use by sub-makes to build libraries for the target 
using the just-built gcc.  Unfortunately, libtool strips off all but 
the first word of the command, and tries to use the result as a 
compiler-driver, which doesn't always work (since it's missing -B 
options and etc.).  The following patch changes libtool to use the full 
compile-command as the compiler driver (while still correctly setting  
cc_basename):

libtool-diffs.txt
Description: Text document