CFLAGS="-Os -g -pipe" LDFLAGS="" CXXFLAGS="-Os -g -pipe" \ CFLAGS='-DPORT_TO_C89 ' \ make -j6 zic=zic cc=arm-linux-gnueabi-gcc ZDUMPDIR=/usr/sbin ZFLAGS="-b slim" make[1]: Entering directory '/home/tzdb-2023c'
That merely tries to set CFLAGS in the environment of 'make', which is ineffective as one can see from the failing command, which was:
arm-linux-gnueabi-gcc -DTZDIR='"/usr/share/zoneinfo"' -c -o asctime.o asctime.c
with no "-DPORT_TO_C89" in sight. I suggest that you instead give a CFLAGS=... argument to 'make', e.g., via this shell command: make -j6 zic=zic cc=arm-linux-gnueabi-gcc \ ZDUMPDIR=/usr/sbin ZFLAGS="-b slim" \ CFLAGS="-Os -g -pipe -DPORT_TO_C89" There's no need to set CXXFLAGS as tzcode doesn't use C++.