Installing fluentd by Ruby gems on Solaris 10: cc: -W option with unknown program all

gem install fluentd -v “~> 0.12.0” --no-ri --no-rdoc

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

/opt/csw/bin/ruby2.0 extconf.rb

checking for ruby/st.h… yes
checking for st.h… yes
checking for rb_str_replace() in ruby.h… yes
checking for rb_intern_str() in ruby.h… yes
checking for rb_sym2str() in ruby.h… no
checking for rb_str_intern() in ruby.h… yes
checking for rb_block_lambda() in ruby.h… yes
checking for rb_hash_dup() in ruby.h… yes
checking for rb_hash_clear() in ruby.h… yes
creating Makefile

make “DESTDIR=”
compiling buffer.c
cc: -W option with unknown program all
*** Error code 1
The following command caused the error:
/opt/SUNWspro/bin/cc -I. -I/opt/csw/include/ruby-2.0.0/i386-solaris2.10 -I/opt/csw/include/ruby-2.0.0/ruby/backward -I/opt/csw/include/ruby-2.0.0 -I. -DHAVE_RUBY_ST_H -DHAVE_ST_H -DHAVE_RB_STR_REPLACE -DHAVE_RB_INTERN_STR -DHAVE_RB_STR_INTERN -DHAVE_RB_BLOCK_LAMBDA -DHAVE_RB_HASH_DUP -DHAVE_RB_HASH_CLEAR -I/opt/csw/include -D_FILE_OFFSET_BITS=64 -KPIC -xO3 -xarch=pentium_pro -xchip=pentium_pro -KPIC -I… -Wall -O3 -g -std=gnu99 -m32 -o buffer.o -c buffer.c
make: Fatal error: Command failed for target `buffer.o’

Gem files will remain installed in /opt/csw/lib/ruby/gems/2.0.0/gems/msgpack-1.3.3 for inspection.
Results logged to /opt/csw/lib/ruby/gems/2.0.0/gems/msgpack-1.3.3/ext/msgpack/gem_make.out

Attempt to install msgpack gem generates the same error as above:

gem install msgpack-1.3.3.gem

Building native extensions. This could take a while…
ERROR: Error installing msgpack-1.3.3.gem:
ERROR: Failed to build gem native extension.

Meanwhile, below given gems have been installed successfully:

gem list --local

*** LOCAL GEMS ***

bigdecimal (1.2.0)
bundler (1.17.3)
concurrent-ruby (1.1.9)
cool.io (1.7.1)
http_parser.rb (0.8.0, 0.6.0)
io-console (0.4.2)
json (2.5.0, 1.7.7)
minitest (4.3.2)
psych (2.0.0)
rake (0.9.6)
rake-compiler (1.1.6)
rdoc (4.0.0)
rubygems-update (2.7.11)
serverengine (1.6.4)
sigdump (0.2.4)
string-scrub (0.0.4)
strptime (0.2.5)
test-unit (2.0.0.0)
tzinfo (2.0.4)
tzinfo-data (1.2021.5)