Fri Dec  4 23:40:12 EET 2009  Sergei Trofimovich <slyfox@inbox.ru>
  * configure.ac: fix libm checks (Trac #3730)
  
  libbfd pulled libm as dependency and broke LIBM= detection.
  
  Patch moves libm in library tests as early as possible.
  Thanks to asuffield for suggesting such a simple fix.
  Thanks to Roie Kerstein and Renato Gallo for finding
  and tracking down the issue.

http://bugs.gentoo.org/show_bug.cgi?id=293208
http://hackage.haskell.org/trac/ghc/ticket/3730
diff -rN -u old-ghc/configure.ac new-ghc/configure.ac
--- old-ghc/configure.ac	2009-12-04 23:51:06.135605014 +0200
+++ new-ghc/configure.ac	2009-12-04 23:51:06.344604339 +0200
@@ -713,18 +713,22 @@
   AC_DEFINE([HAVE_MINGWEX], [1], [Define to 1 if you have the mingwex library.])
 fi
 
-dnl ** check whether this machine has BFD and liberty installed (used for debugging)
-dnl    the order of these tests matters: bfd needs liberty
-AC_CHECK_LIB(iberty, xmalloc)
-AC_CHECK_LIB(bfd,    bfd_init)
-
 dnl ** check for math library
+dnl    Keep that check as early as possible.
+dnl    as we need to know whether we need libm
+dnl    for math functions or not
+dnl    (see http://hackage.haskell.org/trac/ghc/ticket/3730)
 AC_CHECK_FUNC(atan,[fp_libm_not_needed=yes;LIBM=],[fp_libm_not_needed=dunno])
 if test x"$fp_libm_not_needed" = xdunno; then
    AC_CHECK_LIB([m], [atan], [LIBS="-lm $LIBS"; LIBM="-lm"],[LIBM=])
 fi
 AC_SUBST([LIBM])
 
+dnl ** check whether this machine has BFD and liberty installed (used for debugging)
+dnl    the order of these tests matters: bfd needs liberty
+AC_CHECK_LIB(iberty, xmalloc)
+AC_CHECK_LIB(bfd,    bfd_init)
+
 dnl ################################################################
 dnl Check for libraries
 dnl ################################################################