Long story short: Try $> cabal install --extra-include-dirs=/opt/local/include --extra-lib-dirs=/opt/local/lib

I tried it but it still shows the error messages. ~$ cabal install --extra-include-dirs=/opt/local/include --extra-lib-dirs=/opt/local/lib cabal-install Resolving dependencies... Configuring cabal-install-1.22.3.0... Failed to install cabal-install-1.22.3.0 Build log ( /Users/py/.cabal/logs/cabal-install-1.22.3.0.log ): cabal: Error: some packages failed to install: cabal-install-1.22.3.0 failed during the configure step. The exception was: user error ('/usr/bin/ghc' exited with an error: Undefined symbols for architecture x86_64: "_iconv", referenced from: _hs_iconv in libHSbase-4.7.0.1.a(iconv.o) (maybe you meant: _hs_iconv, _base_GHCziIOziEncodingziIconv_iconvEncodingzuloc_info , _base_GHCziIOziEncodingziIconv_iconvEncoding8_info , _base_GHCziIOziEncodingziIconv_iconvEncoding9_closure , _hs_iconv_open , _base_GHCziIOziEncodingziIconv_iconvEncodingzuloc1_closure , _hs_iconv_close , _base_GHCziIOziEncodingziIconv_iconvEncoding6_info , _base_GHCziIOziEncodingziIconv_iconvEncoding4_closure , _base_GHCziIOziEncodingziIconv_iconvEncoding6_closure , _base_GHCziIOziEncodingziIconv_iconvEncoding10_closure , _base_GHCziIOziEncodingziIconv_iconvEncoding7_info , _base_GHCziIOziEncodingziIconv_iconvEncoding2_closure , _base_GHCziIOziEncodingziIconv_iconvEncoding2_info , _base_GHCziIOziEncodingziIconv_iconvEncodingzuloc_closure , _base_GHCziIOziEncodingziIconv_iconvEncoding3_info , _base_GHCziIOziEncodingziIconv_iconvEncoding10_info , _base_GHCziIOziEncodingziIconv_iconvEncoding9_info , _base_GHCziIOziEncodingziIconv_iconvEncoding8_closure , _base_GHCziIOziEncodingziIconv_iconvEncoding7_closure , _base_GHCziIOziEncodingziIconv_iconvEncodingzuloc1_info , _base_GHCziIOziEncodingziIconv_iconvEncoding3_closure ) "_iconv_close", referenced from: _hs_iconv_close in libHSbase-4.7.0.1.a(iconv.o) (maybe you meant: _hs_iconv_close) "_iconv_open", referenced from: _hs_iconv_open in libHSbase-4.7.0.1.a(iconv.o) (maybe you meant: _hs_iconv_open) "_locale_charset", referenced from: _localeEncoding in libHSbase-4.7.0.1.a(PrelIOUtils.o) ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) ) -- Regards, Peng