V2.3.4 make fails on bullseye - multiple definition of `_commands'

[ballle98]

Similar to issue #185. With older versions of gcc you could have duplicate definitions of global variables as long as they are only reference in the files they are defined in. This is no longer allowed and you need to make them static

pi@raspberrypi:~/git/AqualinkD $ make
OS: 11 (bullseye)
GLIBC build with: ldd (Debian GLIBC 2.31-13+rpt2+rpi1+deb11u8) 2.31
GLIBC Prefered  : 2.24-11+deb9u1 2.24
gcc -Wall -O3  -D AQ_PDA -D AQ_ONETOUCH -D AQ_IAQTOUCH -D AQ_RS16 -D AQ_MANAGER -D MG_ENABLE_HTTP_SSI=0 -D MG_ENABLE_DIRECTORY_LISTING=0 -D MG_ENABLE_HTTP_CGI=0  -o release/aqualinkd build/aqualinkd.o build/utils.o build/config.o build/aq_serial.o build/aq_panel.o build/aq_programmer.o build/net_services.o build/json_messages.o build/rs_msg_utils.o build/devices_jandy.o build/packetLogger.o build/devices_pentair.o build/color_lights.o build/serialadapter.o build/aq_timer.o build/aq_scheduler.o build/web_config.o build/serial_logger.o build/mongoose.o build/simulator.o build/timespec_subtract.o build/pda.o build/pda_menu.o build/pda_aq_programmer.o build/onetouch.o build/onetouch_aq_programmer.o build/iaqtouch.o build/iaqtouch_aq_programmer.o -lpthread -lm -lsystemd
/usr/bin/ld: build/simulator.o:(.bss+0x4): multiple definition of `_commands'; build/aq_programmer.o:(.bss+0x8): first defined here
collect2: error: ld returned 1 exit status
make: *** [Makefile:194: release/aqualinkd] Error 1