"differ in signedness" build warnings

Hi,

I'm in the process of porting an application code for a TI Davinci
processor over to the BeagleBoard and when I do a build, I get a bunch
of these "differ in signedness" warnings:

...
main.c
main.c: In function 'NetworkOpen':
main.c:156: warning: pointer targets in passing argument 2 of
'DevCtlBlk.open' differ in signedness
main.c:156: warning: pointer targets in passing argument 3 of
'DevCtlBlk.open' differ in signedness
main.c:176: warning: pointer targets in passing argument 2 of
'DevCtlBlk.open' differ in signedness
main.c:176: warning: pointer targets in passing argument 3 of
'DevCtlBlk.open' differ in signedness
test2.c
test2.c: In function 'netSupEnmTask':
test2.c:1696: warning: pointer targets in passing argument 3 of
'NetworkTransmit' differ in signedness
test2.c:1704: warning: pointer targets in passing argument 3 of
'NetworkTransmit' differ in signedness
test2.c:1712: warning: pointer targets in passing argument 3 of
'NetworkTransmit' differ in signedness
test2.c:1734: warning: pointer targets in passing argument 3 of
'NetworkTransmit' differ in signedness
test1.c
test1.c: In function 'NetworkTimeTask':
test1.c:676: warning: pointer targets in passing argument 1 of
'sprintf' differ in signedness
test1.c: In function 'RxDegreeT':
test1.c:6810: warning: pointer targets in passing argument 1 of
'strtol' differ in signedness
test1.c: In function 'GetWaveform':
test1.c:9051: warning: pointer targets in passing argument 1 of
'strtol' differ in signedness
test1.c: In function 'GetMixedWaveforms':
test1.c:9086: warning: pointer targets in passing argument 1 of
'strtol' differ in signedness
test1.c:9091: warning: pointer targets in passing argument 1 of
'strtol' differ in signedness
test1.c: In function 'GetRePeriod':
test1.c:9121: warning: pointer targets in passing argument 1 of
'strtol' differ in signedness
test1.c: In function 'GetPreambleThreshold':
test1.c:9153: warning: pointer targets in passing argument 1 of
'strtol' differ in signedness
test1.c: In function 'GetTxRate':
test1.c:9173: warning: pointer targets in passing argument 1 of
'strtol' differ in signedness
test1.c:9177: warning: pointer targets in passing argument 1 of
'strlen' differ in signedness
test1.c:9177: warning: pointer targets in passing argument 1 of
'__builtin_strcmp' differ in signedness
test1.c:9177: warning: pointer targets in passing argument 1 of
'strlen' differ in signedness
test1.c:9177: warning: pointer targets in passing argument 1 of
'__builtin_strcmp' differ in signedness
test1.c:9177: warning: pointer targets in passing argument 1 of
'__builtin_strcmp' differ in signedness
test1.c:9177: warning: pointer targets in passing argument 1 of
'__builtin_strcmp' differ in signedness
test1.c: In function 'rpDebugEepromDashDashInfoMessage':
test1.c:9625: warning: pointer targets in passing argument 1 of
'sprintf' differ in signedness
...

And so on. I'm using the arm-2007q3. I didn't get these warnings
with my own TI Davinci toolchain (Montavista Pro Linux). Are these
critical? Where are the all the standard c header files located?
(arm-2007q3/arm-none-linux-gnueabi/libc/usr/include ???)

Can I use the toolchain that got build in the Angstrom (OpenEmbedded
dev) distribution? I noticed the toolchain is located in oe/tmp/cross/
armv7a and quite a few headers are located in oe/tmp/staging/armv7a-
angstrom-linux-gnueabi/usr/include.

I just to figure out the correct header files to include with the
corresponding toolchain. Thanks.

Regards,
Andy

Never mind, those warnings aren't critical; those warnings are related
to typecasting unsigned char to char and vice versa. I guess the TI
Davinci toolchain from the previous platform didn't complain just the
arm-2007q3 toolchain I'm using. Sorry for the noob gcc question but
is there anyway to block these warnings and still use the -Wall
option? Thanks.

Regards,
Andy