mozilla build problem

Hi,

I have been building mozilla, but error messages raised like below:

configure: warning: Cannot build negotiateauth without GSSAPI. Removing
negotatiate from MOZ_EXTENSIONS.
checking for valid optimization flags... no
configure: error: These compiler flags are invalid: -O
*** Fix above errors and then restart with "gnumake -f client.mk build"
gnumake: *** [/Users/macosala/mozdev/mozilla/Makefile] Error 1

I'm suspect I missed some configuration or environment setting, but
cannot find them.

Would you let me know how to solve the problem?

Any information or comments will be appreciated. Thanks and regards..