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>

 diff -Naurd cloog-ppl-0.15.7-a/configure cloog-ppl-0.15.7-b/configure

 --- cloog-ppl-0.15.7-a/configure	2009-08-12 03:33:31.000000000 +0200

 +++ cloog-ppl-0.15.7-b/configure	2012-01-27 13:26:13.970988501 +0100

 @@ -12902,7 +12902,7 @@

  rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext

 -	LIBS="$LIBS -lppl_c -lppl -lgmpxx"

 +	LIBS="-lppl_c -lppl -lgmpxx $LIBS"

  cat >>confdefs.h <<\_ACEOF

  #define CLOOG_PPL_BACKEND 1

 diff -Naurd cloog-ppl-0.15.7-a/configure.in cloog-ppl-0.15.7-b/configure.in

 --- cloog-ppl-0.15.7-a/configure.in	2009-08-12 03:33:31.000000000 +0200

 +++ cloog-ppl-0.15.7-b/configure.in	2012-01-27 13:26:13.970988501 +0100

 @@ -345,7 +345,7 @@

  	#endif

  	], [AC_MSG_RESULT([yes])], [AC_MSG_ERROR(Can't find correct version of PPL.) ])

 -	LIBS="$LIBS -lppl_c -lppl -lgmpxx"

 +	LIBS="-lppl_c -lppl -lgmpxx $LIBS"

  	AC_DEFINE([CLOOG_PPL_BACKEND], 1, [Use the PPL backend])

  else