complibs/cloog: fix linking with libm

In Ubuntu 11.04 and 11.10, the default options for ld have changed.
--no-copy-dt-needed-entries and --as-needed are now enabled by default, which
causes errors like:

[EXTRA] Checking CLooG/ppl
[DEBUG] ==> Executing: 'make' '-j3' '-s' 'check'
[ALL ] Making check in .
[ALL ] config.status: creating include/cloog/cloog-config.h
[ALL ] config.status: include/cloog/cloog-config.h is unchanged
[ALL ] libtool: link: i686-build_pc-linux-gnu-gcc -Wall -fomit-frame-pointer
-pipe -o cloog cloog.o -L/<snip>/build/static/lib ./.libs/libcloog.a -lm
/<snip>/build/static/lib/libppl_c.a /<snip>/build/static/lib/libpwl.a
/<snip>/build/static/lib/libppl.a /<snip>/build/static/lib/libgmpxx.a
/<snip>/build/static/lib/libgmp.a -lstdc++
[ALL ] /usr/bin/ld: /<snip>/build/static/lib/libppl.a(MIP_Problem.o):
undefined reference to symbol 'sqrt@@GLIBC_2.0'
[ALL ] /usr/bin/ld: note: 'sqrt@@GLIBC_2.0' is defined in DSO
/usr/lib/gcc/i686-linux-gnu/4.6.1/../../../i386-linux-gnu/libm.so so try adding
it to the linker command line
[ALL ] /usr/lib/gcc/i686-linux-gnu/4.6.1/../../../i386-linux-gnu/libm.so:
could not read symbols: Invalid operation
[ALL ] collect2: ld returned 1 exit status
[ERROR] make[2]: *** [cloog] Error 1
[ERROR] make[1]: *** [check-recursive] Error 1

See:
https://wiki.ubuntu.com/NattyNarwhal/ToolchainTransition

This patch fixes these errors by placing '-lm' at the right place on the command
line as libppl requires libm when linking cloog.

Signed-off-by: "Benoît Thébaudeau" <benoit.thebaudeau@advansee.com>

 --- ppl-0.10.2/configure.orig	2010-08-04 21:48:19.000000000 -0400

 +++ ppl-0.10.2/configure	2010-08-04 21:50:04.000000000 -0400

 @@ -16443,6 +16443,10 @@

  #GMP version 4.1.3 or higher is required

  #endif

 +#ifndef BITS_PER_MP_LIMB

 +#define BITS_PER_MP_LIMB GMP_LIMB_BITS

 +#endif

 +

  int

  main() {

    std::string header_version;

 @@ -16469,11 +16473,11 @@

      return 1;

    }

 -  if (sizeof(mp_limb_t)*CHAR_BIT != GMP_LIMB_BITS

 -      || GMP_LIMB_BITS != mp_bits_per_limb) {

 +  if (sizeof(mp_limb_t)*CHAR_BIT != BITS_PER_MP_LIMB

 +      || BITS_PER_MP_LIMB != mp_bits_per_limb) {

      std::cerr

        << "GMP header (gmp.h) and library (ligmp.*) bits-per-limb mismatch:\n"

 -      << "header gives " << __GMP_BITS_PER_MP_LIMB << ";\n"

 +      << "header gives " << BITS_PER_MP_LIMB << ";\n"

        << "library gives " << mp_bits_per_limb << ".\n"

        << "This probably means you are on a bi-arch system and\n"

        << "you are compiling with the wrong header or linking with\n"