On Thu, Jul 1, 2021 at 11:22 AM Andrew Rybchenko
[off-list ref] wrote:

The build works fine for me on FC34, but it has
libatomic-11.1.1-3.fc34.x86_64 installed.

I first produced the issue on my "old" FC32.
Afaics, for FC33 and later, gcc now depends on libatomic and the
problem won't be noticed.
FC32 and before are EOL, but I then reproduced the issue on RHEL 8
(and Intel CI reported it on Centos 8 too).

I'd like to understand what we're trying to solve here.
Are we trying to make meson to report the missing library
correctly?

If so, I think I can do simple check using cc.links()
which will fail if the library is not found. I'll
test that it works as expected if the library is not
completely installed.

I tried below diff, and it works for me.
"works" as in net/sfc gets disabled without libatomic installed:

diff --git a/drivers/net/sfc/meson.build b/drivers/net/sfc/meson.build
index 32b58e3d76..8d62aad774 100644
--- a/drivers/net/sfc/meson.build
+++ b/drivers/net/sfc/meson.build

@@ -15,6 +15,7 @@ endif
 if (arch_subdir != 'x86' or not dpdk_conf.get('RTE_ARCH_64')) and

(arch_subdir != 'arm' or not
host_machine.cpu_family().startswith('aarch64'))
     build = false
     reason = 'only supported on x86_64 and aarch64'
+    subdir_done()
 endif

 extra_flags = []

@@ -46,6 +47,14 @@ endif

 # for gcc compiles we need -latomic for 128-bit atomic ops
 if cc.get_id() == 'gcc'
+    code = '''#include <stdio.h>
+    void main() { printf("Atomilink me.\n"); }
+    '''
+    if not cc.links(code, args: '-latomic', name: 'libatomic link check')
+        build = false
+        reason = 'missing dependency, "libatomic"'
+        subdir_done()
+    endif
     ext_deps += cc.find_library('atomic')
 endif

-- 
David Marchand