Problem building gcc

[arslabs]

I tried to build gcc in Mac OS X 10.7.5, but link error occurred.

.....
gcc -g -fkeep-inline-functions -DIN_GCC -W -Wall -Wwrite-strings -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wmissing-format-attribute -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Wold-style-definition -Wc++-compat -fno-common -DHAVE_CONFIG_H -o cc1 c-lang.o c-family/stub-objc.o attribs.o c-errors.o c-decl.o c-typeck.o c-convert.o c-aux-info.o c-objc-common.o c-parser.o tree-mudflap.o c-family/c-common.o c-family/c-cppbuiltin.o c-family/c-dump.o c-family/c-format.o c-family/c-gimplify.o c-family/c-lex.o c-family/c-omp.o c-family/c-opts.o c-family/c-pch.o c-family/c-ppoutput.o c-family/c-pragma.o c-family/c-pretty-print.o c-family/c-semantics.o c-family/c-ada-spec.o i386-c.o darwin-c.o
cc1-checksum.o main.o tree-browser.o libbackend.a ../libcpp/libcpp.a ../libdecnumber/libdecnumber.a ../libcpp/libcpp.a ./../intl/libintl.a -liconv ../libiberty/libiberty.a ../libdecnumber/libdecnumber.a -L/opt/local/lib -L/opt/local/lib -L/opt/local/lib -lmpc -lmpfr -lgmp -L../zlib -lz
Undefined symbols for architecture x86_64:
"_iconv", referenced from:
_convert_using_iconv in libcpp.a(charset.o)
__nl_find_msg in libintl.a(dcigettext.o)
(maybe you meant: __cpp_destroy_iconv, _cpp_init_iconv )
"_iconv_close", referenced from:
__cpp_destroy_iconv in libcpp.a(charset.o)
__cpp_convert_input in libcpp.a(charset.o)
__nl_free_domain_conv in libintl.a(loadmsgcat.o)
"_iconv_open", referenced from:
_init_iconv_desc in libcpp.a(charset.o)
__nl_init_domain_conv in libintl.a(loadmsgcat.o)
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status

How can I solve this?