From 7f446f002ccc137f061630e68f87e5c5d3cc86b2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20G=C3=B3rny?= <mgorny@gentoo.org>
Date: Tue, 25 Oct 2022 11:39:38 +0200
Subject: [PATCH] gh-98636: Fix detecting gdbm_compat for _dbm module

Fix the gdbm_compat library detection logic to actually check for
-lgdbm_compat independently of the ndbm detection.  This fixes the build
failure with `--with-dbmliborder=gdbm`, and implicit fallback to ndbm
with the default value.
---
 Misc/ACKS                                     |  1 +
 ...2-10-25-11-53-55.gh-issue-98636.e0RPAr.rst |  2 +
 configure                                     | 59 +++++--------------
 configure.ac                                  |  4 +-
 4 files changed, 20 insertions(+), 46 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Build/2022-10-25-11-53-55.gh-issue-98636.e0RPAr.rst

diff --git a/Misc/ACKS b/Misc/ACKS
index d50cb3c2d1ee4fa..169afc6eb383e49 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -640,6 +640,7 @@ Tiago Gonçalves
 Chris Gonnerman
 Shelley Gooch
 David Goodger
+Michał Górny
 Elliot Gorokhovsky
 Hans de Graaff
 Tim Graham
diff --git a/Misc/NEWS.d/next/Build/2022-10-25-11-53-55.gh-issue-98636.e0RPAr.rst b/Misc/NEWS.d/next/Build/2022-10-25-11-53-55.gh-issue-98636.e0RPAr.rst
new file mode 100644
index 000000000000000..26a7cc8acaf2434
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2022-10-25-11-53-55.gh-issue-98636.e0RPAr.rst
@@ -0,0 +1,2 @@
+Fix a regression in detecting ``gdbm_compat`` library for the ``_gdbm``
+module build.
diff --git a/configure b/configure
index 3f8daf9dad5fd80..23642b668d4d3f8 100755
--- a/configure
+++ b/configure
@@ -14748,18 +14748,13 @@ fi
 { ac_cv_header_gdbm_ndbm_h=; unset ac_cv_header_gdbm_ndbm_h;}
 
 if test "$ac_cv_header_gdbm_slash_ndbm_h" = yes -o "$ac_cv_header_gdbm_dash_ndbm_h" = yes; then
-  save_CFLAGS=$CFLAGS
-save_CPPFLAGS=$CPPFLAGS
-save_LDFLAGS=$LDFLAGS
-save_LIBS=$LIBS
-
-
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing dbm_open" >&5
-$as_echo_n "checking for library containing dbm_open... " >&6; }
-if ${ac_cv_search_dbm_open+:} false; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dbm_open in -lgdbm_compat" >&5
+$as_echo_n "checking for dbm_open in -lgdbm_compat... " >&6; }
+if ${ac_cv_lib_gdbm_compat_dbm_open+:} false; then :
   $as_echo_n "(cached) " >&6
 else
-  ac_func_search_save_LIBS=$LIBS
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lgdbm_compat  $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -14778,44 +14773,22 @@ return dbm_open ();
   return 0;
 }
 _ACEOF
-for ac_lib in '' gdbm_compat; do
-  if test -z "$ac_lib"; then
-    ac_res="none required"
-  else
-    ac_res=-l$ac_lib
-    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
-  fi
-  if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_search_dbm_open=$ac_res
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_gdbm_compat_dbm_open=yes
+else
+  ac_cv_lib_gdbm_compat_dbm_open=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext
-  if ${ac_cv_search_dbm_open+:} false; then :
-  break
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
 fi
-done
-if ${ac_cv_search_dbm_open+:} false; then :
-
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_gdbm_compat_dbm_open" >&5
+$as_echo "$ac_cv_lib_gdbm_compat_dbm_open" >&6; }
+if test "x$ac_cv_lib_gdbm_compat_dbm_open" = xyes; then :
+  have_gdbm_compat=yes
 else
-  ac_cv_search_dbm_open=no
+  have_gdbm_compat=no
 fi
-rm conftest.$ac_ext
-LIBS=$ac_func_search_save_LIBS
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_dbm_open" >&5
-$as_echo "$ac_cv_search_dbm_open" >&6; }
-ac_res=$ac_cv_search_dbm_open
-if test "$ac_res" != no; then :
-  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
-
-fi
-
-
-CFLAGS=$save_CFLAGS
-CPPFLAGS=$save_CPPFLAGS
-LDFLAGS=$save_LDFLAGS
-LIBS=$save_LIBS
-
 
 fi
 
diff --git a/configure.ac b/configure.ac
index 734a4db83899151..421f4457624876c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4147,9 +4147,7 @@ AS_VAR_IF([ac_cv_header_gdbm_dash_ndbm_h], [yes], [
 AS_UNSET([ac_cv_header_gdbm_ndbm_h])
 
 if test "$ac_cv_header_gdbm_slash_ndbm_h" = yes -o "$ac_cv_header_gdbm_dash_ndbm_h" = yes; then
-  WITH_SAVE_ENV([
-    AC_SEARCH_LIBS([dbm_open], [gdbm_compat])
-  ])
+  AC_CHECK_LIB(gdbm_compat, dbm_open, [have_gdbm_compat=yes], [have_gdbm_compat=no])
 fi
 
 # Check for libdb >= 5 with dbm_open()