Ruby 1.9 support would be very much appreciated.
Here's my output:

$ sudo gem install gbarcode
Building native extensions.  This could take a while...
ERROR:  Error installing gbarcode:
	ERROR: Failed to build gem native extension.

/usr/local/bin/ruby extconf.rb install gbarcode
creating Makefile

make
gcc -I. -I/usr/local/include/ruby-1.9.1/i386-darwin9.6.0 -I/usr/local/include/ruby-1.9.1/ruby/backward
-I/usr/local/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -O3 -g -Wall -Wno-unused-parameter
-Wno-parentheses -Wno-missing-field-initializers -Wshorten-64-to-32 -Wpointer-arith -Wwrite-strings  -pipe  -o barcode_wrap.o
-c barcode_wrap.c
In file included from barcode_wrap.c:1558:
/usr/local/include/ruby-1.9.1/ruby/backward/rubyio.h:2:2: warning: #warning use "ruby/io.h" instead of
"rubyio.h"
barcode_wrap.c: In function ‘SWIG_AsCharPtrAndSize’:
barcode_wrap.c:1670: warning: implicit declaration of function ‘STR2CSTR’
barcode_wrap.c:1670: warning: initialization makes pointer from integer without a cast
barcode_wrap.c: In function ‘_wrap_barcode_print’:
barcode_wrap.c:1830: error: ‘OpenFile’ undeclared (first use in this function)
barcode_wrap.c:1830: error: (Each undeclared identifier is reported only once
barcode_wrap.c:1830: error: for each function it appears in.)
barcode_wrap.c:1830: error: ‘of’ undeclared (first use in this function)
barcode_wrap.c:1833: warning: implicit declaration of function ‘GetWriteFile’
barcode_wrap.c:1833: warning: assignment makes pointer from integer without a cast
barcode_wrap.c: In function ‘_wrap_barcode_encode_and_print’:
barcode_wrap.c:1882: error: ‘OpenFile’ undeclared (first use in this function)
barcode_wrap.c:1882: error: ‘of’ undeclared (first use in this function)
barcode_wrap.c:1885: warning: assignment makes pointer from integer without a cast
barcode_wrap.c: In function ‘_wrap_barcode_svg_print’:
barcode_wrap.c:1940: error: ‘OpenFile’ undeclared (first use in this function)
barcode_wrap.c:1940: error: ‘of’ undeclared (first use in this function)
barcode_wrap.c:1943: warning: assignment makes pointer from integer without a cast
barcode_wrap.c:1945: warning: implicit declaration of function ‘Barcode_svg_print’
make: *** [barcode_wrap.o] Error 1

Date: 2009-09-22 19:43
Sender: Andreas Haller

Here's a fixed Version for Ruby 1.9
http://github.com/ahaller/gbarcode