65 lines
3.0 KiB
Diff
65 lines
3.0 KiB
Diff
https://github.com/unrealircd/unrealircd/pull/242
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From 3246e472842237ac9e655e254380c4dd8fea7abc Mon Sep 17 00:00:00 2001
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From: Sam James <sam@gentoo.org>
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Date: Sun, 18 Dec 2022 06:18:51 +0000
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Subject: [PATCH] configure.ac: fix -Wimplicit-function-declaration
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Clang 16 makes -Wimplicit-function-declaration error by default.
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Unfortunately, this can lead to misconfiguration or miscompilation of software as configure
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tests may then return the wrong result.
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We also fix -Wstrict-prototypes while here as it's easy to do and it prepares
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us for C23.
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Fixes the following:
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```
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configure:6250: checking if your system has IPv6 support
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configure:6275: x86_64-pc-linux-gnu-gcc -o conftest -O2 -pipe -march=native -fdiagnostics-color=always -frecord-gcc-switches -Wreturn-type -ggdb3 -Werror=implicit-function-declaration -Werror=implicit-int -fno-strict-aliasing -fno-common -funsigned-char -Wall -Wextra -Waggregate-return -Wformat-nonliteral -Wduplicated-cond -Wduplicated-branches -Wparentheses -Wno-pointer-sign -Wno-format-zero-length -Wno-format-truncation -Wno-format-overflow -Wno-unused -Wno-unused-parameter -Wno-unused-but-set-parameter -Wno-char-subscripts -Wno-sign-compare -Wno-empty-body -Wno-pragmas -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0 -Wl,-z,pack-relative-relocs conftest.c >&5
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conftest.c: In function 'main':
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conftest.c:30:1: error: implicit declaration of function 'exit' [-Werror=implicit-function-declaration]
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30 | exit(0); /* We only check if the code compiles, that's enough. We can deal with missing runtime IPv6 */
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| ^~~~
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conftest.c:28:1: note: include '<stdlib.h>' or provide a declaration of 'exit'
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27 | #include <sys/socket.h>
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+++ |+#include <stdlib.h>
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28 | int main() {
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conftest.c:30:1: warning: incompatible implicit declaration of built-in function 'exit' [-Wbuiltin-declaration-mismatch]
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30 | exit(0); /* We only check if the code compiles, that's enough. We can deal with missing runtime IPv6 */
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| ^~~~
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conftest.c:30:1: note: include '<stdlib.h>' or provide a declaration of 'exit'
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cc1: some warnings being treated as errors
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configure:6275: $? = 1
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```
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For more information, see LWN.net [0] or LLVM's Discourse [1], the Gentoo wiki [2],
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or the (new) c-std-porting mailing list [3].
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[0] https://lwn.net/Articles/913505/
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[1] https://discourse.llvm.org/t/configure-script-breakage-with-the-new-werror-implicit-function-declaration/65213
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[2] https://wiki.gentoo.org/wiki/Modern_C_porting
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[3] hosted at lists.linux.dev.
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--- a/configure.ac
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+++ b/configure.ac
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@@ -326,7 +326,7 @@ fi
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])
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AC_CACHE_CHECK(if your system prepends an underscore on symbols,ac_cv_underscore,[
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cat >uscore.c << __EOF__
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-int main() {
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+int main(void) {
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return 0;
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}
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__EOF__
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@@ -354,7 +354,8 @@ AC_CACHE_CHECK([if your system has IPv6 support], [ac_cv_ip6], [
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AC_TRY_RUN([
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#include <sys/types.h>
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#include <sys/socket.h>
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-int main() {
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+#include <stdlib.h>
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+int main(void) {
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int s = socket(AF_INET6, SOCK_STREAM, 0);
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exit(0); /* We only check if the code compiles, that's enough. We can deal with missing runtime IPv6 */
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}
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