Redmine

I tried to install (upgrade) puma without success on my Windows 7 64 bit machine. Here is what I received:

D:\apps\redmine_svn>gem install puma
Building native extensions.  This could take a while...
ERROR:  Error installing puma:
        ERROR: Failed to build gem native extension.

    C:/Ruby193/bin/ruby.exe extconf.rb
creating Makefile

make
generating puma_http11-i386-mingw32.def
compiling http11_parser.c
ext/http11/http11_parser.rl: In function 'puma_parser_execute':
ext/http11/http11_parser.rl:111:3: warning: comparison between signed and unsigned integer expressions
compiling io_buffer.c
io_buffer.c: In function 'buf_to_str':
io_buffer.c:119:3: warning: pointer targets in passing argument 1 of 'rb_str_new' differ in signedness
c:/Ruby193/include/ruby-1.9.1/ruby/intern.h:653:7: note: expected 'const char *' but argument is of type 'uint8_t *'
compiling mini_ssl.c
In file included from mini_ssl.c:3:0:
c:/Ruby193/include/ruby-1.9.1/ruby/backward/rubyio.h:2:2: warning: #warning use "ruby/io.h" instead of "rubyio.h" 
mini_ssl.c:4:25: fatal error: openssl/bio.h: No such file or directory
compilation terminated.
make: *** [mini_ssl.o] Error 1

Gem files will remain installed in C:/Ruby193/lib/ruby/gems/1.9.1/gems/puma-2.6.0 for inspection.
Results logged to C:/Ruby193/lib/ruby/gems/1.9.1/gems/puma-2.6.0/ext/puma_http11/gem_make.out

D:\apps\redmine_svn>

Something related to openssl. Is there someone experienced such problem?

Ivan