Can't install ‘ferret’ gem on Mac OS X Snow Leopard

I can't install the ferret gem in my computer with:

gem install ferret

Here is the error:

macbookpro:tehago davidpombarlourido$ sudo gem install ferret
Password:
Building native extensions.  This could take a while...
ERROR:  Error installing ferret:
    ERROR: Failed to build gem native extension.

        /Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/bin/ruby extconf.rb
creating Makefile

make
gcc -I. -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe -D_FILE_OFFSET_BITS=64  -o analysis.o -c analysis.c
analysis.c: In function ‘w_tk_set’:
analysis.c:46: warning: implicit conversion shortens 64-bit value into a 32-bit value
analysis.c: In functio开发者_Python百科n ‘mb_next_char’:
analysis.c:165: warning: implicit conversion shortens 64-bit value into a 32-bit value
analysis.c: In function ‘nt_next’:
analysis.c:249: warning: implicit conversion shortens 64-bit value into a 32-bit value
analysis.c: In function ‘hf_next’:
analysis.c:1240: warning: implicit conversion shortens 64-bit value into a 32-bit value
analysis.c:1282: warning: implicit conversion shortens 64-bit value into a 32-bit value
analysis.c:1284: warning: implicit conversion shortens 64-bit value into a 32-bit value
analysis.c:1285: warning: implicit conversion shortens 64-bit value into a 32-bit value
analysis.c: In function ‘mb_lcf_next’:
analysis.c:1315: warning: implicit conversion shortens 64-bit value into a 32-bit value
analysis.c:1321: warning: implicit conversion shortens 64-bit value into a 32-bit value
gcc -I. -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe -D_FILE_OFFSET_BITS=64  -o api.o -c api.c
gcc -I. -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe -D_FILE_OFFSET_BITS=64  -o array.o -c array.c
gcc -I. -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe -D_FILE_OFFSET_BITS=64  -o bitvector.o -c bitvector.c
gcc -I. -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe -D_FILE_OFFSET_BITS=64  -o compound_io.o -c compound_io.c
compound_io.c: In function ‘cw_copy_file’:
compound_io.c:317: warning: implicit conversion shortens 64-bit value into a 32-bit value
compound_io.c:318: warning: implicit conversion shortens 64-bit value into a 32-bit value
gcc -I. -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe -D_FILE_OFFSET_BITS=64  -o document.o -c document.c
document.c: In function ‘df_new’:
document.c:19: warning: implicit conversion shortens 64-bit value into a 32-bit value
document.c: In function ‘df_add_data’:
document.c:38: warning: implicit conversion shortens 64-bit value into a 32-bit value
document.c: In function ‘df_to_s’:
document.c:58: warning: implicit conversion shortens 64-bit value into a 32-bit value
document.c: In function ‘doc_new’:
document.c:105: warning: implicit conversion shortens 64-bit value into a 32-bit value
document.c: In function ‘doc_to_s’:
document.c:137: warning: implicit conversion shortens 64-bit value into a 32-bit value
gcc -I. -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe -D_FILE_OFFSET_BITS=64  -o except.o -c except.c
except.c:28: warning: initialization discards qualifiers from pointer target type
except.c:29: warning: initialization discards qualifiers from pointer target type
gcc -I. -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/davidpombarlourido/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe -D_FILE_OFFSET_BITS=64  -o ferret.o -c ferret.c
ferret.c: In function ‘rs2s’:
ferret.c:165: error: ‘struct RString’ has no member named ‘ptr’
ferret.c:165: error: ‘struct RString’ has no member named ‘ptr’
ferret.c: In function ‘nstrdup’:
ferret.c:172: error: ‘struct RString’ has no member named ‘len’
ferret.c: In function ‘frt_field’:
ferret.c:183: warning: return discards qualifiers from pointer target type
ferret.c: In function ‘vfrt_rb_raise’:
ferret.c:254: warning: format not a string literal and no format arguments
ferret.c: In function ‘frt_term_to_s’:
ferret.c:297: error: ‘struct RString’ has no member named ‘len’
ferret.c:297: error: ‘struct RString’ has no member named ‘len’
make: *** [ferret.o] Error 1


Gem files will remain installed in /Users/davidpombarlourido/.rvm/gems/ruby-1.9.2-p180/gems/ferret-0.11.6 for inspection.
Results logged to /Users/davidpombarlourido/.rvm/gems/ruby-1.9.2-p180/gems/ferret-0.11.6/ext/gem_make.out

I had the same bug and I solved it by installing another gem :

gem install sdsykes-ferret

I'm using ruby 1.9.2 and I think the gem "ferret" doesn't work on it.

There is an open issue about that on Github : here