$ LDFLAGS="-arch x86_64" ./configure --prefix=/usr/local --with-mysql=/usr/local/mysql

checking build environment
--------------------------

checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for gawk... no
checking for mawk... no
checking for nawk... no
checking for awk... awk
checking whether make sets $(MAKE)... yes
checking whether to enable maintainer-specific portions of Makefiles... no

checking for compiler programs
------------------------------

checking whether to compile debug version... no
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... configure: error: cannot run C compiled programs.
If you meant to cross compile, use `--host'.
See `config.log' for more details.
intention@Macintosh Mon Aug 11 15:41:10 ~/Downloads/sphinx-0.9.8
$ make
Making all in src
if test -d ../.svn; then svn info .. --xml | perl svnxrev.pl; fi;
make  all-am
g++  -Wall -g -D_FILE_OFFSET_BITS=64 -O3 -DNDEBUG   -o indexer  indexer.o libsphinx.a  -arch ppc64 -L/usr/local/mysql/lib -lmysqlclient -lz -lm  -lexpat  -L/usr/local/lib
ld warning: in /usr/local/lib/libexpat.dylib, file is not of required architecture
Undefined symbols:
  "_XML_SetUserData", referenced from:
      CSphSource_XMLPipe2::Connect(CSphString&)       in libsphinx.a(sphinx.o)
  "_XML_SetElementHandler", referenced from:
      CSphSource_XMLPipe2::Connect(CSphString&)       in libsphinx.a(sphinx.o)
  "_XML_SetCharacterDataHandler", referenced from:
      CSphSource_XMLPipe2::Connect(CSphString&)       in libsphinx.a(sphinx.o)
  "_XML_ErrorString", referenced from:
      CSphSource_XMLPipe2::ParseNextChunk(int, CSphString&)    in libsphinx.a(sphinx.o)
  "_XML_GetErrorCode", referenced from:
      CSphSource_XMLPipe2::ParseNextChunk(int, CSphString&)    in libsphinx.a(sphinx.o)
  "_XML_ParserCreate", referenced from:
      CSphSource_XMLPipe2::Connect(CSphString&)       in libsphinx.a(sphinx.o)
  "_XML_Parse", referenced from:
      CSphSource_XMLPipe2::ParseNextChunk(int, CSphString&)    in libsphinx.a(sphinx.o)
  "_XML_ParserFree", referenced from:
      CSphSource_XMLPipe2::Disconnect()       in libsphinx.a(sphinx.o)
      CSphSource_XMLPipe2::~CSphSource_XMLPipe2()in libsphinx.a(sphinx.o)
      CSphSource_XMLPipe2::~CSphSource_XMLPipe2()in libsphinx.a(sphinx.o)
  "_XML_GetCurrentLineNumber", referenced from:
      CSphSource_XMLPipe2::UnexpectedCharaters(char const*, int, char const*)in libsphinx.a(sphinx.o)
      CSphSource_XMLPipe2::Characters(char const*, int)in libsphinx.a(sphinx.o)
      CSphSource_XMLPipe2::ParseNextChunk(int, CSphString&)    in libsphinx.a(sphinx.o)
      CSphSource_XMLPipe2::DecorateMessageVA(char const*, char*)in libsphinx.a(sphinx.o)
  "_XML_GetCurrentColumnNumber", referenced from:
      CSphSource_XMLPipe2::UnexpectedCharaters(char const*, int, char const*)in libsphinx.a(sphinx.o)
      CSphSource_XMLPipe2::Characters(char const*, int)in libsphinx.a(sphinx.o)
      CSphSource_XMLPipe2::ParseNextChunk(int, CSphString&)    in libsphinx.a(sphinx.o)
      CSphSource_XMLPipe2::DecorateMessageVA(char const*, char*)in libsphinx.a(sphinx.o)
ld: symbol(s) not found
collect2: ld returned 1 exit status
make[2]: *** [indexer] Error 1
make[1]: *** [all] Error 2
make: *** [all-recursive] Error 1