Re: --with-libgmp-prefix

[Paul Emsley]

On 28/06/11 13:45, Paul Emsley wrote:
> Hi,
>
> I don't understand how the --with-libgmp-prefix is supposed to work.
>
> In fact, I'd go as far as saying that it's broken.
>
> ./configure --with-libgmp-prefix=/opt
>
> in configure additional_includedir and additional_libdir get set correctly
>
> but in config.log, I see:
>
> configure:36897: checking for libgmp
> configure:36919: gcc -o conftest -g -O2   conftest.c -lcrypt -lm  -lgmp>&5
> conftest.c:569:17: fatal error: gmp.h: No such file or directory
>
> ... that is (AFAICS), additional_includedir and additional_libdir are
> not being used (in AC_LIB_HAVE_LINKFLAGS?)

Additional info:

If I configure with --with-libgmp=/opt (given my reading of 
|AC_LIB_HAVE_LINKFLAGS documentation):

https://www.gnu.org/software/gnulib/manual/html_node/Searching-for-Libraries.html
|
then:

checking for libgmp... no
configure: error: GNU MP 4.1 or greater not found, see README

configure:36897: checking for libgmp
configure:36919: gcc -o conftest -g -O2   conftest.c /opt/lib/libgmp.so 
-Wl,-rpath -Wl,/opt/lib -lcrypt -lm >&5
conftest.c:569:17: fatal error: gmp.h: No such file or directory
compilation terminated.

Incidentally, configure complains about that:

configure: WARNING: unrecognized options: --with-libgmp

Nevertheless, I believe that that is progress, configure knows how to 
handle the library at least.

If I set CPPFLAGS=-I/opt/include, then:

configure:36897: checking for libgmp
configure:36919: gcc -o conftest -g -O2 -I/opt/include  conftest.c 
/opt/lib/libgmp.so -Wl,-rpath -Wl,/opt/lib -lcrypt -lm >&5
configure:36919: $? = 0
configure:36929: result: yes
configure:36936: checking how to link with libgmp
configure:36938: result: /opt/lib/libgmp.so -Wl,-rpath -Wl,/opt/lib

OK, that worked.  But using CPPFLAGS is a hack - and should not be 
needed for libgmp dependency (IMHO).

Cheers,

Paul.