This is a duplicate of http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48725.

My GCC version is 4.6.0 release, working under Ubuntu 10.10 x64.
gcc -###
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/.../x86_64-gcc-4.6.0/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --prefix=/.../x86_64-gcc-4.6.0 --enable-shared
--with-arch=native --enable-languages=c,c++ --enable-lto --enable-plugin
--enable-gold --enable-linker-build-id --disable-multilib --enable-ld=default
--with-plugin-ld=ld.gold
Thread model: posix
gcc version 4.6.0 (GCC)

It uses binutils 2.21.51, installed with the same prefix "/.../x86_64-gcc-4.6.0".
ld.gold --version
GNU gold (GNU Binutils 2.21.51.20110414) 1.11
Copyright 2011 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.

I make p7zip 9.20.1, downloadable at p7zip.sourceforge.net. I use makefile
named makefile.linux_amd64 with the following addition:

OPTFLAGS=-O2 -flto

When it comes to linking 7z.so, I get the following:
...

make[1]: Entering directory `/???/p7zip_9.20.1/CPP/7zip/Bundles/Format7zFree'
g++ -m64 -O2 -flto -pipe -s -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DNDEBUG
-D_REENTRANT -DENV_UNIX -D_7ZIP_LARGE_PAGES -fPIC -DEXTERNAL_CODECS -DUNICODE
-D_UNICODE -fPIC -shared -o ../../../../bin/7z.so  wine_date_and_time.o
myGetTickCount.o CRC.o IntToString.o MyMap.o MyString.o MyWindows.o MyXml.o
StringConvert.o StringToInt.o MyVector.o UTFConvert.o Wildcard.o  FileDir.o
FileFind.o FileIO.o PropVariant.o PropVariantUtils.o Synchronization.o System.o
Time.o  InBuffer.o InOutTempBuffer.o CreateCoder.o CWrappers.o FilterCoder.o
LimitedStreams.o LockedStream.o MethodId.o MethodProps.o MemBlocks.o
OffsetStream.o OutBuffer.o OutMemStream.o ProgressMt.o ProgressUtils.o
StreamBinder.o StreamObjects.o StreamUtils.o VirtThread.o  ArchiveExports.o
DllExports2.o ApmHandler.o ArjHandler.o Bz2Handler.o CpioHandler.o
CramfsHandler.o DebHandler.o DeflateProps.o DmgHandler.o ElfHandler.o
FatHandler.o FlvHandler.o GzHandler.o LzhHandler.o LzmaHandler.o MachoHandler.o
MbrHandler.o MslzHandler.o MubHandler.o NtfsHandler.o PeHandler.o PpmdHandler.o
RpmHandler.o SplitHandler.o SwfHandler.o SquashfsHandler.o VhdHandler.o
XarHandler.o XzHandler.o ZHandler.o  CoderMixer2.o CoderMixer2MT.o
CrossThreadProgress.o DummyOutStream.o FindSignature.o InStreamWithCRC.o
ItemNameUtils.o MultiStream.o OutStreamWithCRC.o OutStreamWithSha1.o
HandlerOut.o ParseProperties.o  7zCompressionMode.o 7zDecode.o 7zEncode.o
7zExtract.o 7zFolderInStream.o 7zFolderOutStream.o 7zHandler.o 7zHandlerOut.o
7zHeader.o 7zIn.o 7zOut.o 7zProperties.o 7zSpecStream.o 7zUpdate.o 7zRegister.o
 CabBlockInStream.o CabHandler.o CabHeader.o CabIn.o CabRegister.o 
ChmHandler.o ChmHeader.o ChmIn.o ChmRegister.o  ComHandler.o ComIn.o
ComRegister.o  HfsHandler.o HfsIn.o HfsRegister.o  IsoHandler.o IsoHeader.o
IsoIn.o IsoRegister.o  NsisDecode.o NsisHandler.o NsisIn.o NsisRegister.o 
RarHandler.o RarHeader.o RarIn.o RarItem.o RarVolumeInStream.o RarRegister.o 
TarHandler.o TarHandlerOut.o TarHeader.o TarIn.o TarOut.o TarUpdate.o
TarRegister.o  UdfHandler.o UdfIn.o UdfRegister.o  WimHandler.o WimHandlerOut.o
WimIn.o WimRegister.o  ZipAddCommon.o ZipHandler.o ZipHandlerOut.o ZipHeader.o
ZipIn.o ZipItem.o ZipOut.o ZipUpdate.o ZipRegister.o  CodecExports.o
ArjDecoder1.o ArjDecoder2.o Bcj2Coder.o Bcj2Register.o BcjCoder.o BcjRegister.o
BitlDecoder.o BranchCoder.o BranchMisc.o BranchRegister.o ByteSwap.o BZip2Crc.o
BZip2Decoder.o BZip2Encoder.o BZip2Register.o CopyCoder.o CopyRegister.o
Deflate64Register.o DeflateDecoder.o DeflateEncoder.o DeflateRegister.o
DeltaFilter.o Lzma2Decoder.o Lzma2Encoder.o Lzma2Register.o ImplodeDecoder.o
ImplodeHuffmanDecoder.o LzhDecoder.o LzmaDecoder.o LzmaEncoder.o LzmaRegister.o
LzOutWindow.o Lzx86Converter.o LzxDecoder.o PpmdDecoder.o PpmdEncoder.o
PpmdRegister.o PpmdZip.o QuantumDecoder.o ShrinkDecoder.o ZlibDecoder.o
ZlibEncoder.o ZDecoder.o  7zAes.o 7zAesRegister.o HmacSha1.o MyAes.o
Pbkdf2HmacSha1.o RandGen.o Rar20Crypto.o RarAes.o Sha1.o WzAes.o ZipCrypto.o
ZipStrong.o  7zBuf2.o 7zStream.o Aes.o Alloc.o Bra.o Bra86.o BraIA64.o
BwtSort.o Delta.o HuffEnc.o LzFind.o LzFindMt.o Lzma2Dec.o Lzma2Enc.o LzmaDec.o
LzmaEnc.o MtCoder.o Ppmd7.o Ppmd7Dec.o Ppmd7Enc.o Ppmd8.o Ppmd8Dec.o Ppmd8Enc.o
Sha256.o Sort.o Threads.o Xz.o XzCrc64.o XzDec.o XzEnc.o XzIn.o  7zCrc.o
7zCrcOpt.o  -lpthread -ldl
/.../x86_64-gcc-4.6.0/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../x86_64-unknown-linux-gnu/bin/ld.gold:
internal error in symtab_section, at ../../gold/layout.h:684
collect2: ld returned 1 exit status
make[1]: *** [../../../../bin/7z.so] Error 1


With "-fuse-linker-plugin" added, I get the same error.