Fix compilation issues on OpenBSD

[millert]

This PR fixes the following issues that prevent building syslog-ng on OpenBSD:

• OpenBSD uses a different flavor of reentrant getent functions
• OpenBSD doesn't support IPv4-mapped IPv6 addresses (they are considered harmful)
• OpenBSD uses IP_RECVDSTADDR for UDP dest-IP like FreeBSD does
• tlscontext.c uses AF_INET and AF_INET6 but doesn't include sys/socket.h where they are defined.

[kira-syslogng]

This user does not have permission to start the build. Can one of the admins verify this patch and start the build?
(admin: you have the next options (make sure you checked the code):
"ok to test" to accept this pull request (and further changes) for testing
"test this please" for a one time test run
"add to whitelist" add author of a Pull Request to whitelist (globally, be careful, it means this user can trigger kira for any PR)
do nothing -> CI won't start)

[kira-syslogng]

This user does not have permission to start the build. Can one of the admins verify this patch and start the build?
(admin: you have the next options (make sure you checked the code):
"ok to test" to accept this pull request (and further changes) for testing
"test this please" for a one time test run
"add to whitelist" add author of a Pull Request to whitelist (globally, be careful, it means this user can trigger kira for any PR)
do nothing -> CI won't start)

[Kokan]

@kira-syslogng ok to test

[kira-syslogng]

Build SUCCESS

[Kokan]

Thanks for the patches.

[kira-syslogng]

Build SUCCESS

[MrAnno]

Thank you for this pull request!

One thing I noticed is that getent-openbsd.c is not built, the following lines seem to be missing from our build files:

diff --git a/lib/compat/CMakeLists.txt b/lib/compat/CMakeLists.txt
index 92330189d..2e2511c65 100644
--- a/lib/compat/CMakeLists.txt
+++ b/lib/compat/CMakeLists.txt
@@ -11,6 +11,7 @@ set(COMPAT_HEADERS
     compat/pcre.h
     compat/getent.h
     compat/getent-sun.h
+    compat/getent-openbsd.h
     compat/getent-generic.h
     compat/un.h
     PARENT_SCOPE)
@@ -27,6 +28,7 @@ set(COMPAT_SOURCES
     compat/time.c
     compat/openssl_support.c
     compat/getent-sun.c
+    compat/getent-openbsd.c
     compat/getent-generic.c
     PARENT_SCOPE)

diff --git a/lib/compat/Makefile.am b/lib/compat/Makefile.am
index d537b3914..968e154fe 100644
--- a/lib/compat/Makefile.am
+++ b/lib/compat/Makefile.am
@@ -17,6 +17,7 @@ compatinclude_HEADERS         =       \
        lib/compat/pcre.h               \
        lib/compat/getent.h             \
        lib/compat/getent-sun.h         \
+       lib/compat/getent-openbsd.h \
        lib/compat/getent-generic.h     \
        lib/compat/un.h

@@ -32,6 +33,7 @@ compat_sources                        =       \
        lib/compat/time.c               \
        lib/compat/openssl_support.c    \
        lib/compat/getent-sun.c         \
+       lib/compat/getent-openbsd.c \
        lib/compat/getent-generic.c

 include lib/compat/tests/Makefile.am

[MrAnno]

I was able to compile this PR with the above Makefile patch on OpenBSD 6.9 (bison 3.7.6 compiled from source, gmake).

NULL was undeclared, but including stddef.h fixed it:

../lib/compat/getent-openbsd.c: In function '_compat_openbsd__getprotobynumber_r':
../lib/compat/getent-openbsd.c:38: error: 'NULL' undeclared (first use in this function)

diff --git a/lib/compat/getent-openbsd.c b/lib/compat/getent-openbsd.c
index 1b1af9eaf..ca36fb07b 100644
--- a/lib/compat/getent-openbsd.c
+++ b/lib/compat/getent-openbsd.c
@@ -25,6 +25,7 @@

 #ifdef __OpenBSD__
 #include <errno.h>
+#include <stddef.h>

 int
 _compat_openbsd__getprotobynumber_r(int proto,

[millert]

@MrAnno Thanks, I came up with an identical fix for the compilation error.

[kira-syslogng]

Build SUCCESS

[MrAnno]

Thank you.