On a sunny day (Fri, 06 Mar 2020 11:07:05 -0500) it happened Dennis Lee Bieber
 wrote in :

>On Fri, 06 Mar 2020 13:52:06 GMT, Jan Panteltje 
>declaimed the following:
>
>
>>
>>Pi4 compiler gives a lot of weird warnings, I like clean compiles reads
faster,
>>no idea what this is supposed to mean:
>> /usr/include/features.h:184:3: warning: #warning "_BSD_SOURCE and
_SVID_SOURCE are deprecated, use _DEFAULT_SOURCE" [-Wcpp]
>>
>
>        Unless you have different compiler/OS versions running on the various
>machines, I'd expect all R-Pi models to produce the same warnings for the
>same input. What happens if you swap the SD card between the models and
>repeat?
>
>        As for the warning itself, I'd suspect the listed include file is
>making use of something like
>
>#ifdef xxxx
>
>referencing either of those two definitions. Though... a quick google shows
>a solution to be in a makefile (for something)
>https://pagure.io/jss/issue/raw/files/18027bfb0e34eebcd4ebbc137c0443e2fdee90d5
394778f0d15fb961c1278cf9-fix4Warnings.patch
>https://stackoverflow.com/questions/29201515/what-does-d-default-source-do

Interesting, just tried some things, Pi4 keeps complaining..
It runs gcc version 8.3.0 (Raspbian 8.3.0-6+rpi1):

raspi95: ~/compile/pantel/xgpspc # make
cc -O2 -Wall   -c -o graphics.o graphics.c
In file included from /usr/include/arm-linux-gnueabihf/sys/types.h:25,
                 from xgpspc.h:42,
                 from graphics.c:26:
/usr/include/features.h:184:3: warning: #warning "_BSD_SOURCE and _SVID_SOURCE
are deprecated, use _DEFAULT_SOURCE" [-Wcpp]
 # warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
...

Exactly the same source and same Makefile on Pi2 is a clean compile;

That runs gcc version 4.6.3 (Debian 4.6.3-14+rpi1):

root@raspi73:~/compile/pantel/xgpspc# rm graphics.o
root@raspi73:~/compile/pantel/xgpspc# make
cc -DWITH_MAIN -Wall -O2 -I/usr/local/include -Wall  -c -o graphics.o
graphics.c
gcc -o xgpspc xgpspc.o setup.o mpu6050.o sensors.o iiclib.o io.o x11.o
graphics.o ais.o navigation.o hmc5883.o bmp180.o nmea.o markeringen.o alarms.o
stepper.o udp_server.o planes.o -lm -lpthread -lXaw -ljpeg

Also clean on the X86 laptop.. it runs gcc version 4.5.2 (GCC) (slackware).
panteltje20: ~ # uname -a
Linux panteltje20 2.6.37.6 #3 SMP Sat Apr 9 22:49:32 CDT 2011 x86_64 Intel(R)
Core(TM) i5-2430M CPU @ 2.40GHz GenuineIntel GNU/Linux
time flies :-)

Will play with it and gcc options a bit more,
clearly is a compiler issue.

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