meson: disable LTO in HAVE_AS_FUNC check

When LTO is enabled using -flto, simply compiling does not
produce an error. Either LTO must be turned off or a linking check must
be performed. LTO does not seem to affect non-assembly checks.

This behaviour can be seen in the following test:

    $ cat t.c
    int main(void)
    {
        __asm__ (".foobar this_directive_doesnt_exist");
        return 0;
    }
    $ cc t.c -o t.o -flto -c
    $ echo $?
    0
    $ cc t.c -o t.o -flto
    ld: <inline asm>:1:2: unknown directive
        .foobar this_directive_doesnt_exist
        ^
     for architecture arm64
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    $ echo $?
    1

Signed-off-by: J. Dekker <jdek@itanimul.li>

meson.build

@@ -346,7 +346,7 @@ if (is_asm_enabled and
 ".endfunc"
 );
 '''
-    have_as_func = cc.compiles(as_func_code)
+    have_as_func = cc.compiles(as_func_code, args: '-fno-lto')
     cdata.set10('HAVE_AS_FUNC', have_as_func)
 
     # fedora package build infrastructure uses a gcc specs file to enable