share/zoneinfo: use gcc

[saper]

When building on FreeBSD 14, "cc" is clang 16. This makes the build fail like this:

cd zoneinfo; make  
cc  -O -g -Wall -Werror -idirafter /big/sw/discobsd/include -c zdump.c -o zdump.o
zdump.c:26:1: error: a function definition without a prototype is deprecated in all versions of C and is not supported in C2x [-Werror,-Wdeprecated-non-prototype]
show(zone, t, v)
^
zdump.c:48:1: error: a function definition without a prototype is deprecated in all versions of C and is not supported in C2x [-Werror,-Wdeprecated-non-prototype]
readerr(fp, progname, filename)
^
zdump.c:61:1: error: a function definition without a prototype is deprecated in all versions of C and is not supported in C2x [-Werror,-Wdeprecated-non-prototype]
tzdecode(codep)
^
zdump.c:74:1: error: a function definition without a prototype is deprecated in all versions of C and is not supported in C2x [-Werror,-Wdeprecated-non-prototype]
main(argc, argv)
^
4 errors generated.

quick fix is this:

diff --git a/share/zoneinfo/Makefile b/share/zoneinfo/Makefile
index 7cfd33b..82ed5d9 100644
--- a/share/zoneinfo/Makefile
+++ b/share/zoneinfo/Makefile
@@ -20,7 +20,7 @@ LOCALTIME=    US/Pacific
 
 CFLAGS= -O
 LINTFLAGS=     -phbaxc
-CC=            cc
+CC=            gcc
 CFLAGS+=       -g -Wall -Werror -idirafter $(TOPSRC)/include
 
 TZCSRCS=       zic.c scheck.c ialloc.c

Instead, I could also add -Wno-deprecated-non-prototype but to CFLAGS, but not all compilers might know this.

[chettrick]

I'm working on a commit to add a ${HOST_CC} make variable, similar to how NetBSD handles ${HOST_CC} in /tools, to remedy the issues like this one.

At least it will make it easy to do:

$ make HOST_CC=some_specific_compiler_name

for any OS that needs it, while not affecting ${CC} in the rest of the build.

[saper]

Great, this was just a stop-gap measure to get it build in my series of patches to get it working on my FreeBSD.
Which gcc are you using normally?

gcc 11 seems to be a bit too new to compile this, not to mention clang 16 I have now in -CURRENT.

[saper]

I am a bit confused about how -DCROSS works, especially how can I have a cross-tool like ar that partially uses host headers like, say <stdio.h> and our target headers.

[chettrick]

This issue is now not fatal to a build, as -Werror has been removed from ${CFLAGS} in 1947277, and 8498986 for /share/zoneinfo specifically. It is now only a warning with Clang 16.

I will leave this issue open until zoneinfo has been fixed properly.

[chettrick]

I'm working on a commit to add a ${HOST_CC} make variable, similar to how NetBSD handles ${HOST_CC} in /tools, to remedy the issues like this one.

At least it will make it easy to do:

$ make HOST_CC=some_specific_compiler_name

for any OS that needs it, while not affecting ${CC} in the rest of the build.

The commit d853304 implements and enables the ${HOST_CC} make variable throughout the build.