Review conf_syslibs.py: fix check_funcs return value and minor cleanup.

- pyconf.py / pyconf.awk: check_funcs/pyconf_check_funcs now return True/1
  if any function was found, matching AC_CHECK_FUNCS action-if-found semantics.
  Previously returned None/0, causing the backtrace/dladdr1 check in
  check_base_libraries to never set ac_cv_require_ldl, so -ldl was never
  added to LDFLAGS for faulthandler support.
- conf_syslibs.py: fix module docstring (remove incorrect "pthreads setup",
  add missing check_stat_timestamps and setup_tzpath descriptions).
- conf_syslibs.py: initialize r and libatomic_needed before with-blocks to
  avoid Pyright possibly-unbound warnings.

Assisted-by: Claude

Author: nascheme

Tools/configure/conf_syslibs.py

@@ -1,12 +1,11 @@
-"""conf_syslibs — GDBM, DBM, pthreads setup, base libraries, libatomic.
+"""conf_syslibs — GDBM, DBM, base libraries, libatomic, stat timestamps, tzpath.
 
 Detects GDBM library and headers; handles --with-dbmliborder and
 detects DBM backends (gdbm, ndbm, bdb) in the specified order;
-configures POSIX threads (THREADOBJ, thread CFLAGS/LDFLAGS,
-PTHREAD_SYSTEM_SCHED_SUPPORTED); probes for sendfile, dl, dld
-libraries and backtrace/dladdr1 support; checks sem_init, intl,
-AIX-specific extensions, and aligned memory access; and probes
-whether libatomic is needed for <pyatomic.h>.
+probes for sendfile, dl, dld libraries and backtrace/dladdr1 support;
+checks sem_init, intl, AIX-specific extensions, and aligned memory access;
+probes whether libatomic is needed for <pyatomic.h>; checks for subsecond
+timestamps in struct stat; and handles --with-tzpath.
 """
 
 from __future__ import annotations
@@ -106,6 +105,7 @@ def detect_dbm(v):
         )
 
     if ac_cv_header_gdbm_slash_ndbm_h or ac_cv_header_gdbm_dash_ndbm_h:
+        r = ""
         with pyconf.save_env():
             r = pyconf.search_libs("dbm_open", ["gdbm_compat"], required=False)
         if r and r is not False:
@@ -298,6 +298,7 @@ def check_libatomic(v):
     # anymore.  <pyport.h> cannot be included alone, it's designed to be included
     # by <Python.h>: it expects other includes and macros to be defined.
 
+    libatomic_needed = False
     with pyconf.save_env():
         v.CPPFLAGS = f"{v.BASECPPFLAGS} -I. -I{pyconf.srcdir}/Include {v.CPPFLAGS}".strip()
         libatomic_needed = not pyconf.link_check(

Tools/configure/pyconf.py

@@ -3170,12 +3170,20 @@ def check_func(
     return found
 
 
-def check_funcs(funcs: list[str], headers: list[str] | None = None) -> None:
-    """AC_CHECK_FUNCS — check multiple functions; define HAVE_<FUNC> for each found."""
+def check_funcs(funcs: list[str], headers: list[str] | None = None) -> bool:
+    """AC_CHECK_FUNCS — check multiple functions; define HAVE_<FUNC> for each found.
+
+    Returns True if any function was found (matches AC_CHECK_FUNCS action-if-found
+    semantics, where the action runs for each found function).
+    """
+    any_found = False
     for f in funcs:
         checking(f"for {f}")
         found = check_func(f, headers=headers)
         result(found)
+        if found:
+            any_found = True
+    return any_found
 
 
 def check_decl(

Tools/configure/transpiler/pyconf.awk

@@ -762,14 +762,18 @@ function pyconf_check_func(fname, headers, define, source, inc, cv, rc, cache_ke
         return rc
 }
 
-function pyconf_check_funcs(funcs, n, i, rc) {
+function pyconf_check_funcs(funcs,    n, i, rc, any_found) {
+        # Returns 1 if any function was found (mirrors AC_CHECK_FUNCS action-if-found).
         n = funcs[0] + 0
+        any_found = 0
         for (i = 1; i <= n; i++)
                 if (funcs[i] != "") {
                         pyconf_checking("for " funcs[i])
                         rc = pyconf_check_func(funcs[i])
                         pyconf_result(rc ? "yes" : "no")
+                        if (rc) any_found = 1
                 }
+        return any_found
 }
 
 function pyconf_replace_funcs(funcs, n, i, rc) {