squib installation problems

gistfile1.txt

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

    /Users/louiserains/.rbenv/versions/2.2.1/bin/ruby -r ./siteconf20150629-66096-vrc64y.rb extconf.rb
checking for --enable-debug-build option... no
checking for -Wall option to compiler... yes
checking for -Waggregate-return option to compiler... yes
checking for -Wcast-align option to compiler... yes
checking for -Wextra option to compiler... yes
checking for -Wformat=2 option to compiler... yes
checking for -Winit-self option to compiler... yes
checking for -Wlarger-than-65500 option to compiler... yes
checking for -Wmissing-declarations option to compiler... yes
checking for -Wmissing-format-attribute option to compiler... yes
checking for -Wmissing-include-dirs option to compiler... yes
checking for -Wmissing-noreturn option to compiler... yes
checking for -Wmissing-prototypes option to compiler... yes
checking for -Wnested-externs option to compiler... yes
checking for -Wold-style-definition option to compiler... yes
checking for -Wpacked option to compiler... yes
checking for -Wp,-D_FORTIFY_SOURCE=2 option to compiler... yes
checking for -Wpointer-arith option to compiler... yes
checking for -Wswitch-default option to compiler... yes
checking for -Wswitch-enum option to compiler... yes
checking for -Wundef option to compiler... yes
checking for -Wout-of-line-declaration option to compiler... yes
checking for -Wunsafe-loop-optimizations option to compiler... no
checking for -Wwrite-strings option to compiler... yes
checking for rb_define_alloc_func() in ruby.h... yes
checking for rb_block_proc() in ruby.h... yes
checking for new allocation framework... yes
checking for attribute assignment... no
checking for cairo... yes
checking for rb_cairo.h... yes
checking for Windows... no
checking for librsvg-2.0... no
checking for brew... yes
installing 'librsvg' native package... failed
failed to run 'brew install librsvg'.
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
	--with-opt-dir
	--without-opt-dir
	--with-opt-include
	--without-opt-include=${opt-dir}/include
	--with-opt-lib
	--without-opt-lib=${opt-dir}/lib
	--with-make-prog
	--without-make-prog
	--srcdir=.
	--curdir
	--ruby=/Users/louiserains/.rbenv/versions/2.2.1/bin/$(RUBY_BASE_NAME)
	--enable-debug-build
	--disable-debug-build
	--with-pkg-config
	--without-pkg-config
	--with-override-variables
	--without-override-variables

extconf failed, exit code 1

Gem files will remain installed in /Users/louiserains/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/rsvg2-2.2.5 for inspection.
Results logged to /Users/louiserains/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/extensions/x86_64-darwin-14/2.2.0-static/rsvg2-2.2.5/gem_make.out