Compile problem on Mac OS X 10.4/gcc 4.0

[Per P. <per...@ma...>]

Hi,
I've had a report that gnuplot won't compile on OS X 10.4 and gcc 4.0 
because of a conflict with a static char array "Class" in gplt_x11.c 
and the Objective-C type "Class". It has not been a problem before so 
it seems gcc 4 is pickier about this than gcc 3.x.

I haven't upgraded to 10.4 yet, but I thought that I could be 
"pro-active" and fix it anyway...

When detecting Mac OS X and libaquaterm "-ObjC" is added to CFLAGS 
(apple.m4), and every file is compiled as ObjC although only 
aquaterm.trm needs the "-ObjC" flag.
As I see it, there are two ways to fix this:
1) Change the name "Class" in gplt_x11.c
2) Increase granularity in buildsystem to only compile aquaterm.trm (or 
term.c) with "-ObjC"

Obviously, (2) is the right thing to do, but I have to confess that I 
don't understand how to properly change the build system to achieve 
that. Suggestions would be appreciated.

/Per