warnings compiling Emacs 22 on amd64

[Francesco Potorti`]

I get these warnings during compilation on x86_64-unknown-linux-gnu with
Debian testing with gcc (GCC) 4.1.2 20061028 (prerelease) (Debian 4.1.1-19)

I identified the reason for the first one and posted it on emacs-devel,
where I am going to follow up the answer I got.  I plan to consider the
other warnings too, but that may take time, so if anyone else considers
this and gives me patches to try, I will.


gcc -c -D_BSD_SOURCE   -Demacs -DHAVE_CONFIG_H   -I. 
-I/home/pot/gnu/emacs-22.0.91/src -D_BSD_SOURCE  -g -O2 -Wno-pointer-sign  
dispnew.c
dispnew.c: In function 'init_display':
dispnew.c:6895: warning: overflow in implicit constant conversion
dispnew.c:6896: warning: overflow in implicit constant conversion

gcc -c -D_BSD_SOURCE   -Demacs -DHAVE_CONFIG_H   -I. 
-I/home/pot/gnu/emacs-22.0.91/src -D_BSD_SOURCE  -g -O2 -Wno-pointer-sign  
editfns.c
editfns.c: In function 'Fuser_uid':
editfns.c:1317: warning: comparison is always false due to limited range of 
data type
editfns.c:1317: warning: comparison is always false due to limited range of 
data type
editfns.c: In function 'Fuser_real_uid':
editfns.c:1325: warning: comparison is always false due to limited range of 
data type
editfns.c:1325: warning: comparison is always false due to limited range of 
data type

gcc -c -D_BSD_SOURCE   -Demacs -DHAVE_CONFIG_H   -I. 
-I/home/pot/gnu/emacs-22.0.91/src -D_BSD_SOURCE  -g -O2 -Wno-pointer-sign  fns.c
fns.c: In function 'maybe_resize_hash_table':
fns.c:4684: warning: comparison is always false due to limited range of data 
type

gcc -c -D_BSD_SOURCE   -Demacs -DHAVE_CONFIG_H   -I. 
-I/home/pot/gnu/emacs-22.0.91/src -D_BSD_SOURCE  -g -O2 -Wno-pointer-sign  
process.c
process.c: In function 'Fdelete_process':
process.c:820: warning: comparison is always false due to limited range of data 
type
process.c:820: warning: comparison is always false due to limited range of data 
type
process.c:830: warning: comparison is always false due to limited range of data 
type
process.c:830: warning: comparison is always false due to limited range of data 
type
process.c: In function 'Fprocess_id':
process.c:917: warning: comparison is always false due to limited range of data 
type
process.c:917: warning: comparison is always false due to limited range of data 
type
process.c: In function 'Fsignal_process':
process.c:6114: warning: cast from pointer to integer of different size
process.c: In function 'sigchld_handler':
process.c:6441: warning: comparison is always false due to limited range of 
data type
process.c:6441: warning: comparison is always false due to limited range of 
data type

gcc -Demacs -DHAVE_CONFIG_H   -I. -I/home/pot/gnu/emacs-22.0.91/src 
-D_BSD_SOURCE  -g -O2 -Wno-pointer-sign  -Wl,-znocombreloc 
/home/pot/gnu/emacs-22.0.91/src/prefix-args.c -o prefix-args
/home/pot/gnu/emacs-22.0.91/src/prefix-args.c: In function 'main':
/home/pot/gnu/emacs-22.0.91/src/prefix-args.c:64: warning: incompatible 
implicit declaration of built-in function 'exit'
/home/pot/gnu/emacs-22.0.91/src/prefix-args.c:73: warning: incompatible 
implicit declaration of built-in function 'exit'