[igt-dev] [PATCH i-g-t 2/7] meson: Don't redefine gettid if the C library provides it

[Lyude]

From: Lyude Paul <lyude at redhat.com>

glibc 2.30+ will actually include a definition for gettid() that makes
it so that users don't have to manually define a wrapper for it
themselves with syscall(). We don't currently check for this, and as a
result will end up redefining gettid() on the latest versions of glibc,
causing the build to fail:

FAILED: lib/76b5a35@@igt-igt_kmod_c at sta/igt_kmod.c.o
In file included from /usr/include/unistd.h:1170,
                 from ../../mnt/vol/lib/igt_core.h:43,
                 from ../../mnt/vol/lib/igt_kmod.c:28:
/usr/include/bits/unistd_ext.h:34:28: error: macro "gettid" passed 1 arguments, but takes just 0
   34 | extern __pid_t gettid (void) __THROW;
      |                            ^
In file included from ../../mnt/vol/lib/igt_kmod.c:27:
../../mnt/vol/lib/igt_aux.h:40: note: macro "gettid" defined here
   40 | #define gettid() syscall(__NR_gettid)
      |
[36/771] Compiling C object 'lib/76b5a35@@igt-igt_kms_c at sta/igt_kms.c.o'.
ninja: build stopped: subcommand failed.

So, fix this by by adding some meson checks to define HAVE_GETTID whenever the
host defines its own gettid(), and avoid redefining gettid() when HAVE_GETTID is
defined.

This fixes build intel-gpu-tools for me on Fedora Rawhide

Signed-off-by: Lyude Paul <lyude at redhat.com>
---
 lib/igt_aux.h | 3 +++
 meson.build   | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/lib/igt_aux.h b/lib/igt_aux.h
index 55392790..39fefcbf 100644
--- a/lib/igt_aux.h
+++ b/lib/igt_aux.h
@@ -36,7 +36,10 @@
 #include <i915/gem_submission.h>
 
 /* signal interrupt helpers */
+#ifndef HAVE_GETTID
 #define gettid() syscall(__NR_gettid)
+#endif
+
 #define sigev_notify_thread_id _sigev_un._tid
 
 /* auxialiary igt helpers from igt_aux.c */
diff --git a/meson.build b/meson.build
index 557400a5..e73275dd 100644
--- a/meson.build
+++ b/meson.build
@@ -237,6 +237,9 @@ if cc.has_header('cpuid.h')
 	# FIXME: Do we need the example link test from configure.ac?
 	config.set('HAVE_CPUID_H', 1)
 endif
+if cc.has_header_symbol('unistd.h', 'gettid', args : '-D_GNU_SOURCE')
+	config.set('HAVE_GETTID', 1)
+endif
 
 if cc.has_member('struct sysinfo', 'totalram',
 		prefix : '#include <sys/sysinfo.h>')
-- 
2.20.1