Merge bitcoin/bitcoin#30074: contrib: use ENV flags in get_arch

b59a027d95 contrib: drop dead get_machine from test sym check (fanquake)
e6aba463ad contrib: use env_flags in get_arch (fanquake)

Pull request description:

  This isn't an issue right now (because the get_arch check is simple), but becomes one as soon as we want to use `lld` for linking, and need LDFLAGS (otherwise we call `ld` and fail, see it's usage in #21778). So I've split this out for review. It also makes sense to use the same flags for all compilation in these checks.

  Also drops some dead code in test-symbol-check.

ACKs for top commit:
  TheCharlatan:
    ACK b59a027d95

Tree-SHA512: d8afc4144815369aae63cf6dc6e983af46f208c7043d6ea5c9c811152649c256a8e67eb6864ea9d385d87b6b049fece07710a84b90da325da7fc3f05efcaacd6

contrib/devtools/test-security-check.py

@@ -27,22 +27,24 @@ def clean_files(source, executable):
     os.remove(source)
     os.remove(executable)
 
-def call_security_check(cc: str, source: str, executable: str, options) -> tuple:
+def env_flags() -> list[str]:
     # This should behave the same as AC_TRY_LINK, so arrange well-known flags
     # in the same order as autoconf would.
     #
     # See the definitions for ac_link in autoconf's lib/autoconf/c.m4 file for
     # reference.
-    env_flags: list[str] = []
+    flags: list[str] = []
     for var in ['CFLAGS', 'CPPFLAGS', 'LDFLAGS']:
-        env_flags += filter(None, os.environ.get(var, '').split(' '))
+        flags += filter(None, os.environ.get(var, '').split(' '))
+    return flags
 
-    subprocess.run([*cc,source,'-o',executable] + env_flags + options, check=True)
+def call_security_check(cc: str, source: str, executable: str, options) -> tuple:
+    subprocess.run([*cc,source,'-o',executable] + env_flags() + options, check=True)
     p = subprocess.run([os.path.join(os.path.dirname(__file__), 'security-check.py'), executable], stdout=subprocess.PIPE, text=True)
     return (p.returncode, p.stdout.rstrip())
 
 def get_arch(cc, source, executable):
-    subprocess.run([*cc, source, '-o', executable], check=True)
+    subprocess.run([*cc, source, '-o', executable] + env_flags(), check=True)
     binary = lief.parse(executable)
     arch = binary.abstract.header.architecture
     os.remove(executable)

contrib/devtools/test-symbol-check.py

@@ -27,10 +27,6 @@ def call_symbol_check(cc: list[str], source, executable, options):
     os.remove(executable)
     return (p.returncode, p.stdout.rstrip())
 
-def get_machine(cc: list[str]):
-    p = subprocess.run([*cc,'-dumpmachine'], stdout=subprocess.PIPE, text=True)
-    return p.stdout.rstrip()
-
 class TestSymbolChecks(unittest.TestCase):
     def test_ELF(self):
         source = 'test1.c'