dev-ruby/rcairo-1.10.2-r1 failed on OSX prefix enviroment

gistfile1.txt

syuus-MacBook:~ syuu$ USE=-aqua ~/Gentoo/usr/bin/emerge --autounmask-write y -v rcairo

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These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N    *] dev-ruby/rcairo-1.10.2-r1  USE="-doc -test" RUBY_TARGETS="ruby19 (-ree18) -ruby18" 0 kB

Total: 1 package (1 new), Size of downloads: 0 kB


>>> Verifying ebuild manifests

>>> Emerging (1 of 1) dev-ruby/rcairo-1.10.2-r1
 * cairo-1.10.2.gem RMD160 SHA1 SHA256 size ;-) ...                      [ ok ]
>>> Unpacking source...
 * Running unpack phase for all ...
 * Unpacking .gem file... ...                                            [ ok ]
 * Uncompressing metadata ...                                            [ ok ]
 * Unpacking data.tar.gz ...                                             [ ok ]
>>> Source unpacked in /Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/work
>>> Preparing source in /Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/work ...
 * Running prepare phase for all ...
 * Running source copy phase for ruby19 ...
>>> Source prepared.
>>> Configuring source in /Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/work ...
 * Running configure phase for ruby19 ...
checking for GCC... yes
checking for Win32 OS... no
checking for Mac OS X... yes
checking for cairo version (>= 1.2.0)... yes
checking for HAVE_RUBY_ST_H in ruby.h... yes
checking for HAVE_RUBY_IO_H in ruby.h... yes
checking for rb_errinfo() in ruby.h... yes
checking for enum ruby_value_type in ruby.h... yes
creating Makefile
>>> Source configured.
>>> Compiling source in /Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/work ...
 * Running compile phase for ruby19 ...
make -Cext/cairo 
make: Entering directory `/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/work/ruby19/rcairo-1.10.2/ext/cairo'
compiling rb_cairo.c
compiling rb_cairo_constants.c
compiling rb_cairo_context.c
compiling rb_cairo_device.c
compiling rb_cairo_exception.c
compiling rb_cairo_font_extents.c
compiling rb_cairo_font_face.c
compiling rb_cairo_font_options.c
compiling rb_cairo_glyph.c
compiling rb_cairo_io.c
compiling rb_cairo_matrix.c
compiling rb_cairo_path.c
compiling rb_cairo_pattern.c
compiling rb_cairo_private.c
compiling rb_cairo_region.c
compiling rb_cairo_scaled_font.c
compiling rb_cairo_surface.c
compiling rb_cairo_text_cluster.c
compiling rb_cairo_text_extents.c
linking shared-object cairo.bundle
make: Leaving directory `/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/work/ruby19/rcairo-1.10.2/ext/cairo'
 * Running compile phase for all ...
>>> Source compiled.
>>> Test phase [not enabled]: dev-ruby/rcairo-1.10.2-r1

>>> Install rcairo-1.10.2-r1 into /Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/image/ category dev-ruby
 * Running install phase for ruby19 ...
-------------------------------------------------------
You should not use ${EPREFIX} with helpers.
  --> /Users/syuu/Gentoo/usr/include/ruby-1.9.1
-------------------------------------------------------
 * ERROR: dev-ruby/rcairo-1.10.2-r1 failed (install phase):
 *   Cannot install header file.
 * 
 * Call stack:
 *     ebuild.sh, line   98:  Called call-ebuildshell 'src_install'
 *   environment, line  537:  Called src_install
 *   environment, line 4259:  Called ruby-ng_src_install
 *   environment, line 3960:  Called _ruby_each_implementation 'each_ruby_install'
 *   environment, line  293:  Called _ruby_invoke_environment 'ruby19' 'each_ruby_install'
 *   environment, line  345:  Called each_ruby_install
 *   environment, line  686:  Called die
 * The specific snippet of code:
 *       doins ext/cairo/rb_cairo.h || die "Cannot install header file."
 * 
 * If you need support, post the output of 'emerge --info =dev-ruby/rcairo-1.10.2-r1',
 * the complete build log and the output of 'emerge -pqv =dev-ruby/rcairo-1.10.2-r1'.
!!! When you file a bug report, please include the following information:
GENTOO_VM=  CLASSPATH="" JAVA_HOME=""
JAVACFLAGS="" COMPILER=""
and of course, the output of emerge --info
 * The complete build log is located at '/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/temp/build.log'.
 * The ebuild environment file is located at '/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/temp/environment'.
 * S: '/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/work/ruby19/rcairo-1.10.2'

>>> Failed to emerge dev-ruby/rcairo-1.10.2-r1, Log file:

>>>  '/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/temp/build.log'

 * Messages for package dev-ruby/rcairo-1.10.2-r1:

 * ERROR: dev-ruby/rcairo-1.10.2-r1 failed (install phase):
 *   Cannot install header file.
 * 
 * Call stack:
 *     ebuild.sh, line   98:  Called call-ebuildshell 'src_install'
 *   environment, line  537:  Called src_install
 *   environment, line 4259:  Called ruby-ng_src_install
 *   environment, line 3960:  Called _ruby_each_implementation 'each_ruby_install'
 *   environment, line  293:  Called _ruby_invoke_environment 'ruby19' 'each_ruby_install'
 *   environment, line  345:  Called each_ruby_install
 *   environment, line  686:  Called die
 * The specific snippet of code:
 *       doins ext/cairo/rb_cairo.h || die "Cannot install header file."
 * 
 * If you need support, post the output of 'emerge --info =dev-ruby/rcairo-1.10.2-r1',
 * the complete build log and the output of 'emerge -pqv =dev-ruby/rcairo-1.10.2-r1'.
 * The complete build log is located at '/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/temp/build.log'.
 * The ebuild environment file is located at '/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/temp/environment'.
 * S: '/Users/syuu/Gentoo/var/tmp/portage/dev-ruby/rcairo-1.10.2-r1/work/ruby19/rcairo-1.10.2'

 * IMPORTANT: 1 news items need reading for repository 'gentoo_prefix'.
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