[gnome-control-center] Fix libm linking

[Bastien Nocera <hadess src gnome org>]

commit a4eef676df12eb8beebd1474427a1b56a7731b50
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Feb 10 18:20:45 2010 +0000

    Fix libm linking
    
    Otherwise we get:
    /usr/bin/ld: gnome-mouse-properties.o: undefined reference to symbol 'floor@@GLIBC_2.0'
    /usr/bin/ld: note: 'floor@@GLIBC_2.0' is defined in DSO /lib/libm.so.6 so try adding it to the linker command line
    /lib/libm.so.6: could not read symbols: Invalid operation
    
    https://bugzilla.gnome.org/show_bug.cgi?id=609570

 configure.ac |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 84eeb3e..a832547 100644
--- a/configure.ac
+++ b/configure.ac
@@ -84,6 +84,8 @@ AC_SUBST(XF86MISC_LIBS)
 AC_CHECK_HEADERS(X11/extensions/XKB.h)
 CPPFLAGS=$savecppflags
 
+AC_CHECK_LIB(m, floor)
+
 dnl ==============================================
 dnl Check that we meet the  dependencies
 dnl ==============================================