How to fix "warning: pointer targets in passing argument X of 'Y' differ in signedness"

[Helge Deller]

When compiling gnokii CVS, gcc prints an awful lot of warning of the type of:
warning: pointer targets in passing argument 1 of 'strncmp' differ in signedness

The reason for that is, that by default gnokii seems to compile with the gcc 
flags "-g -O2".
What I use instead in Makefile.global for CFLAGS to avoid those warnings is:
CFLAGS         = -g -O2 -g -funsigned-char -Wall -Wno-pointer-sign 
-fvisibility=hidden

Would anybody be interested to implement the checks for the additional flags to 
configure.in ?

Helge