buildroot

http://gcc.gnu.org/ml/gcc-patches/2008-10/msg00269.html

​

On glibc the libc.so carries a copy of the math function copysignl() but

on uClibc math functions like copysignl() live in libm. Since libgcc_s

contains unresolved symbols, any attempt to link against libgcc_s

without explicitely specifying -lm fails, resulting in a broken

bootstrap of the compiler.

​

Forward port to gcc 4.5.1 by Gustavo Zacarias <gustavo@zacarias.com.ar>

​

---

 libgcc/Makefile.in  |    4 +++-

 libgcc/configure    |   32 ++++++++++++++++++++++++++++++++

 libgcc/configure.ac |   21 +++++++++++++++++++++

 3 files changed, 56 insertions(+), 1 deletion(-)

​

Index: b/libgcc/Makefile.in

===================================================================

--- a/libgcc/Makefile.in

+++ b/libgcc/Makefile.in

@@ -42,6 +42,7 @@

 enable_vtable_verify = @enable_vtable_verify@

 enable_decimal_float = @enable_decimal_float@

 fixed_point = @fixed_point@

+LIBGCC_LIBM = @LIBGCC_LIBM@

 host_noncanonical = @host_noncanonical@

 target_noncanonical = @target_noncanonical@

@@ -943,9 +944,10 @@

        @multilib_dir@,$(MULTIDIR),$(subst \

        @shlib_objs@,$(objects) libgcc.a,$(subst \

        @shlib_base_name@,libgcc_s,$(subst \

+       @libgcc_libm@,$(LIBGCC_LIBM),$(subst \

        @shlib_map_file@,$(mapfile),$(subst \

        @shlib_slibdir_qual@,$(MULTIOSSUBDIR),$(subst \

-       @shlib_slibdir@,$(shlib_slibdir),$(SHLIB_LINK))))))))

+       @shlib_slibdir@,$(shlib_slibdir),$(SHLIB_LINK)))))))))

 libunwind$(SHLIB_EXT): $(libunwind-s-objects) $(extra-parts)

    # @multilib_flags@ is still needed because this may use

Index: b/libgcc/configure

===================================================================

--- a/libgcc/configure

+++ b/libgcc/configure

@@ -564,6 +564,7 @@

 tmake_file

 sfp_machine_header

 set_use_emutls

+LIBGCC_LIBM

 set_have_cc_tls

 vis_hide

 fixed_point

@@ -4535,6 +4536,37 @@

    fi

 fi

+# On powerpc libgcc_s references copysignl which is a libm function but

+# glibc apparently also provides it via libc as opposed to uClibc where

+# it lives in libm.

+echo "$as_me:$LINENO: checking for library containing copysignl" >&5

+echo $ECHO_N "checking for library containing copysignl... $ECHO_C" >&6

+if test "${libgcc_cv_copysignl_lib+set}" = set; then

+  echo $ECHO_N "(cached) $ECHO_C" >&6