yann@1948: http://gcc.gnu.org/ml/gcc-patches/2008-10/msg00269.html
yann@1948: 
yann@1948: On glibc the libc.so carries a copy of the math function copysignl() but
yann@1948: on uClibc math functions like copysignl() live in libm. Since libgcc_s
yann@1948: contains unresolved symbols, any attempt to link against libgcc_s
yann@1948: without explicitely specifying -lm fails, resulting in a broken
yann@1948: bootstrap of the compiler.
yann@1948: 
yann@1948: 
yann@1948: diff -durN gcc-4.4.4.orig/gcc/config/t-slibgcc-elf-ver gcc-4.4.4/gcc/config/t-slibgcc-elf-ver
yann@1948: --- gcc-4.4.4.orig/gcc/config/t-slibgcc-elf-ver	2010-01-04 16:13:08.000000000 +0100
yann@1948: +++ gcc-4.4.4/gcc/config/t-slibgcc-elf-ver	2010-05-16 19:38:36.000000000 +0200
yann@1948: @@ -9,7 +9,7 @@
yann@1948:  SHLIB_OBJS = @shlib_objs@
yann@1948:  SHLIB_DIR = @multilib_dir@
yann@1948:  SHLIB_SLIBDIR_QUAL = @shlib_slibdir_qual@
yann@1948: -SHLIB_LC = -lc
yann@1948: +SHLIB_LC = @libgcc_libm@ -lc
yann@1948:  SHLIB_MAKE_SOLINK = $(LN_S) $(SHLIB_SONAME) $(SHLIB_DIR)/$(SHLIB_SOLINK)
yann@1948:  SHLIB_INSTALL_SOLINK = $(LN_S) $(SHLIB_SONAME) \
yann@1948:  	$$(DESTDIR)$$(slibdir)$(SHLIB_SLIBDIR_QUAL)/$(SHLIB_SOLINK)
yann@1948: diff -durN gcc-4.4.4.orig/libgcc/Makefile.in gcc-4.4.4/libgcc/Makefile.in
yann@1948: --- gcc-4.4.4.orig/libgcc/Makefile.in	2009-04-10 01:23:07.000000000 +0200
yann@1948: +++ gcc-4.4.4/libgcc/Makefile.in	2010-05-16 19:38:36.000000000 +0200
yann@1948: @@ -39,6 +39,7 @@
yann@1948:  decimal_float = @decimal_float@
yann@1948:  enable_decimal_float = @enable_decimal_float@
yann@1948:  fixed_point = @fixed_point@
yann@1948: +LIBGCC_LIBM = @LIBGCC_LIBM@
yann@1948:  
yann@1948:  host_noncanonical = @host_noncanonical@
yann@1948:  
yann@1948: @@ -787,9 +788,10 @@
yann@1948:  		@multilib_dir@,$(MULTIDIR),$(subst \
yann@1948:  		@shlib_objs@,$(objects),$(subst \
yann@1948:  		@shlib_base_name@,libgcc_s,$(subst \
yann@1948: +		@libgcc_libm@,$(LIBGCC_LIBM),$(subst \
yann@1948:  		@shlib_map_file@,$(mapfile),$(subst \
yann@1948:  		@shlib_slibdir_qual@,$(MULTIOSSUBDIR),$(subst \
yann@1948: -		@shlib_slibdir@,$(shlib_slibdir),$(SHLIB_LINK))))))))
yann@1948: +		@shlib_slibdir@,$(shlib_slibdir),$(SHLIB_LINK)))))))))
yann@1948:  
yann@1948:  libunwind$(SHLIB_EXT): $(libunwind-s-objects) $(extra-parts)
yann@1948:  	# @multilib_flags@ is still needed because this may use
yann@1948: diff -durN gcc-4.4.4.orig/libgcc/configure gcc-4.4.4/libgcc/configure
yann@1948: --- gcc-4.4.4.orig/libgcc/configure	2008-11-20 18:13:01.000000000 +0100
yann@1948: +++ gcc-4.4.4/libgcc/configure	2010-05-16 19:38:36.000000000 +0200
yann@1948: @@ -272,7 +272,7 @@
yann@1948:  PACKAGE_BUGREPORT=''
yann@1948:  
yann@1948:  ac_unique_file="static-object.mk"
yann@1948: -ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS libgcc_topdir enable_shared slibdir INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA AWK build build_cpu build_vendor build_os host host_cpu host_vendor host_os host_noncanonical build_libsubdir build_subdir host_subdir target_subdir AR ac_ct_AR LIPO ac_ct_LIPO NM ac_ct_NM RANLIB ac_ct_RANLIB STRIP ac_ct_STRIP LN_S CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT CPP decimal_float enable_decimal_float fixed_point vis_hide set_have_cc_tls tmake_file extra_parts asm_hidden_op LIBOBJS LTLIBOBJS'
yann@1948: +ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS libgcc_topdir enable_shared slibdir INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA AWK build build_cpu build_vendor build_os host host_cpu host_vendor host_os host_noncanonical build_libsubdir build_subdir host_subdir target_subdir AR ac_ct_AR LIPO ac_ct_LIPO NM ac_ct_NM RANLIB ac_ct_RANLIB STRIP ac_ct_STRIP LN_S CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT CPP decimal_float enable_decimal_float fixed_point vis_hide set_have_cc_tls LIBGCC_LIBM tmake_file extra_parts asm_hidden_op LIBOBJS LTLIBOBJS'
yann@1948:  ac_subst_files=''
yann@1948:  ac_pwd=`pwd`
yann@1948:  
yann@1948: @@ -3547,6 +3547,39 @@
yann@1948:  fi
yann@1948:  
yann@1948:  
yann@1948: +# On powerpc libgcc_s references copysignl which is a libm function but
yann@1948: +# glibc apparently also provides it via libc as opposed to uClibc where
yann@1948: +# it lives in libm.
yann@1948: +echo "$as_me:$LINENO: checking for library containing copysignl" >&5
yann@1948: +echo $ECHO_N "checking for library containing copysignl... $ECHO_C" >&6
yann@1948: +if test "${libgcc_cv_copysignl_lib+set}" = set; then
yann@1948: +  echo $ECHO_N "(cached) $ECHO_C" >&6
yann@1948: +else
yann@1948: +
yann@1948: +    echo '#include <features.h>' > conftest.c
yann@1948: +    echo 'int the_libc = __UCLIBC__ + __powerpc__;' >> conftest.c
yann@1948: +    libgcc_cv_copysignl_lib="-lc"
yann@1948: +    if { ac_try='${CC-cc} -S conftest.c -o conftest.s 1>&5'
yann@1948: +  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
yann@1948: +  (eval $ac_try) 2>&5
yann@1948: +  ac_status=$?
yann@1948: +  echo "$as_me:$LINENO: \$? = $ac_status" >&5
yann@1948: +  (exit $ac_status); }; }
yann@1948: +    then
yann@1948: +	libgcc_cv_copysignl_lib="-lm"
yann@1948: +    fi
yann@1948: +    rm -f conftest.*
yann@1948: +
yann@1948: +fi
yann@1948: +echo "$as_me:$LINENO: result: $libgcc_cv_copysignl_lib" >&5
yann@1948: +echo "${ECHO_T}$libgcc_cv_copysignl_lib" >&6
yann@1948: +
yann@1948: +case /${libgcc_cv_copysignl_lib}/ in
yann@1948: +  /-lm/) LIBGCC_LIBM="$LIBGCC_LIBM -lm" ;;
yann@1948: +  *) LIBGCC_LIBM= ;;
yann@1948: +esac
yann@1948: +
yann@1948: +
yann@1948:  # Conditionalize the makefile for this target machine.
yann@1948:  tmake_file_=
yann@1948:  for f in ${tmake_file}
yann@1948: @@ -4267,6 +4300,7 @@
yann@1948:  s,@fixed_point@,$fixed_point,;t t
yann@1948:  s,@vis_hide@,$vis_hide,;t t
yann@1948:  s,@set_have_cc_tls@,$set_have_cc_tls,;t t
yann@1948: +s,@LIBGCC_LIBM@,$LIBGCC_LIBM,;t t
yann@1948:  s,@tmake_file@,$tmake_file,;t t
yann@1948:  s,@extra_parts@,$extra_parts,;t t
yann@1948:  s,@asm_hidden_op@,$asm_hidden_op,;t t
yann@1948: diff -durN gcc-4.4.4.orig/libgcc/configure.ac gcc-4.4.4/libgcc/configure.ac
yann@1948: --- gcc-4.4.4.orig/libgcc/configure.ac	2008-11-20 18:13:01.000000000 +0100
yann@1948: +++ gcc-4.4.4/libgcc/configure.ac	2010-05-16 19:38:36.000000000 +0200
yann@1948: @@ -223,6 +223,27 @@
yann@1948:  fi
yann@1948:  AC_SUBST(set_have_cc_tls)
yann@1948:  
yann@1948: +# On powerpc libgcc_s references copysignl which is a libm function but
yann@1948: +# glibc apparently also provides it via libc as opposed to uClibc where
yann@1948: +# it lives in libm.
yann@1948: +AC_CACHE_CHECK
yann@1948: +  libgcc_cv_copysignl_lib,
yann@1948: +    echo '#include <features.h>' > conftest.c
yann@1948: +    echo 'int the_libc = __UCLIBC__ + __powerpc__;' >> conftest.c
yann@1948: +    libgcc_cv_copysignl_lib="-lc"
yann@1948: +    if AC_TRY_COMMAND(${CC-cc} -S conftest.c -o conftest.s 1>&AS_MESSAGE_LOG_FD)
yann@1948: +    then
yann@1948: +	libgcc_cv_copysignl_lib="-lm"
yann@1948: +    fi
yann@1948: +    rm -f conftest.*
yann@1948: +  ])
yann@1948: +
yann@1948: +case /${libgcc_cv_copysignl_lib}/ in
yann@1948: +  /-lm/) LIBGCC_LIBM="$LIBGCC_LIBM -lm" ;;
yann@1948: +  *) LIBGCC_LIBM= ;;
yann@1948: +esac
yann@1948: +AC_SUBST(LIBGCC_LIBM)
yann@1948: +
yann@1948:  # Conditionalize the makefile for this target machine.
yann@1948:  tmake_file_=
yann@1948:  for f in ${tmake_file}