build: Stop warning for attribute clang::suppress

That attribute allows us to instruct the Clang Static Analyzer to stop
giving some false positives. However when building the code (with gcc
and clang) they warn that the attribute is ignored. Just ignore as we
know what the attribute is for.

Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/233

configure.ac

@@ -279,6 +279,7 @@ CC_CHECK_FLAGS_APPEND(with_cflags, [CFLAGS], [\
 		       -Wmissing-noreturn \
 		       -Wmissing-prototypes \
 		       -Wnested-externs \
+		       -Wno-attributes=clang::suppress \
 		       -Wno-unused-parameter \
 		       -Wold-style-definition \
 		       -Wpointer-arith \

meson.build

@@ -131,6 +131,7 @@ add_project_arguments(
     '-Wmissing-prototypes',
     '-Wnested-externs',
     '-Wno-unused-parameter',
+    '-Wno-attributes=clang::suppress',
     '-Wold-style-definition',
     '-Wpointer-arith',
     '-Wredundant-decls',