gmp.h installed in wrong place with gmp 4.1.4

[Torbjorn Granlund]

I am not sure the behaviour is incorrect.

>From Makefile.am:

# gmp.h and mp.h are architecture dependent, mainly since they encode the
# limb size used in libgmp.  For that reason they belong under $exec_prefix
# not $prefix, strictly speaking.
#
# $exec_prefix/include is not in the default include path for gcc built to
# the same $prefix and $exec_prefix, which might mean gmp.h is not found,
# but anyone knowledgable enough to be playing with exec_prefix will be able
# to address that.


-- 
Torbjörn