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 options

choice

    bool

    prompt "PPL version"

# Don't remove next line

# CT_INSERT_VERSION_BELOW

config PPL_V_0_11_2

    bool

    prompt "0.11.2 (EXPERIMENTAL)"

    depends on EXPERIMENTAL

    select PPL_0_11

config PPL_V_0_11_1

    bool

    prompt "0.11.1 (EXPERIMENTAL)"

    depends on EXPERIMENTAL

    select PPL_0_11

config PPL_V_0_11

    bool

    prompt "0.11 (EXPERIMENTAL)"

    depends on EXPERIMENTAL

    select PPL_0_11

config PPL_V_0_10_2

    bool

    prompt "0.10.2"

endchoice

config PPL_VERSION

    string

# Don't remove next line

# CT_INSERT_VERSION_STRING_BELOW

    default "0.11.2" if PPL_V_0_11_2

    default "0.11.1" if PPL_V_0_11_1

    default "0.11" if PPL_V_0_11

    default "0.10.2" if PPL_V_0_10_2

# For PPL 0.11, we need to pull libpwl if configured static

config PPL_0_11

    bool

    select PPL_NEEDS_LIBPWL if ! COMPLIBS_SHARED

config PPL_NEEDS_LIBPWL

    bool