[Bug-wget] Build problem on AIX for wget-1.12

[Perry Smith]

On a system that does not have getopt.h in its /usr/include, the build will 
stop when src/main.c is compiled for an "out of tree" build.

The list of -I options does not include one for ../lib which is where getopt.h 
is found.

I worked around it by just editing src/Makefile and adding in some -I paths.

Hope this helps,
Perry Smith