Fix implicit functions for EVP_CIPHER_CTX_cleanup and getgrent_r

From: https://github.com/dun/munge/commit/ede8c9b613f5fce0bedea4f9e71924f4920b9edf
From: https://github.com/dun/munge/commit/deb85536441ab28733e4d8f8a76e5a725afe8ecd
From: https://github.com/dun/munge/commit/9317fe8a7efe692d8c5547c3b5c83dacb2c26872

--- m4/x_ac_check_openssl.m4.orig	2026-02-10 03:07:53.000000000 -0500
+++ m4/x_ac_check_openssl.m4	2026-04-12 19:55:34.982749017 -0400
@@ -124,28 +124,34 @@
 #   and the <INCLUDES> are the prologue of the test source to be linked.
 # The AC_LANG_PROGRAM #undef in the preamble is needed to thwart #define
 #   macros used for backwards-compatibility of deprecated functions.
+# This check only runs if AC_CHECK_FUNCS has determined the function exists
+#   (i.e., ac_cv_func_<NAME> = yes), preventing implicit function declaration
+#   warnings when testing non-existent functions.
 #
 AC_DEFUN([_X_AC_CHECK_OPENSSL_FUNC_RETURNS_INT], [
-  AC_CACHE_CHECK(
-    [if $1 returns int],
-    [ac_cv_func_$1_returns_int], [
-    AS_VAR_SET([ac_cv_func_$1_returns_int], no)
-    AC_LINK_IFELSE([
-      AC_LANG_PROGRAM(
-        [[
+  AS_IF(
+    [test "AS_VAR_GET([ac_cv_func_$1])" = yes], [
+    AC_CACHE_CHECK(
+      [if $1 returns int],
+      [ac_cv_func_$1_returns_int], [
+      AS_VAR_SET([ac_cv_func_$1_returns_int], no)
+      AC_LINK_IFELSE([
+        AC_LANG_PROGRAM(
+          [[
 $3
 #undef $1
 ]],
-        [[int rv = $1 ($2);]]
-      )],
-      AS_VAR_SET([ac_cv_func_$1_returns_int], yes),
-      AS_VAR_SET([ac_cv_func_$1_returns_int], no)
-    )]
-  )
-  AS_IF(
-    [test AS_VAR_GET([ac_cv_func_$1_returns_int]) = yes],
-    AC_DEFINE(AS_TR_CPP([HAVE_$1_RETURN_INT]), [1],
-      [Define to 1 if the `$1' function returns int.]
+          [[int rv = $1 ($2);]]
+        )],
+        AS_VAR_SET([ac_cv_func_$1_returns_int], yes),
+        AS_VAR_SET([ac_cv_func_$1_returns_int], no)
+      )]
     )
+    AS_IF(
+      [test AS_VAR_GET([ac_cv_func_$1_returns_int]) = yes],
+      AC_DEFINE(AS_TR_CPP([HAVE_$1_RETURN_INT]), [1],
+        [Define to 1 if the `$1' function returns int.]
+      )
+    )]
   )]
 )
--- m4/x_ac_getgrent.m4.orig	2026-02-10 03:07:53.000000000 -0500
+++ m4/x_ac_getgrent.m4	2026-04-12 19:57:35.898190342 -0400
@@ -18,17 +18,41 @@
 
 AC_DEFUN([X_AC_GETGRENT], [
   AC_CHECK_FUNCS(getgrent)
+  _X_AC_GETGRENT_CHECK_WNO_IMPLICIT
+  _x_ac_getgrent_cflags_save="${CFLAGS}"
+  _x_ac_getgrent_werror_save="${ac_c_werror_flag}"
+  CFLAGS="${CFLAGS} ${x_ac_getgrent_wno_implicit_flag}"
+  ac_c_werror_flag=yes
   _X_AC_GETGRENT_R_AIX
   _X_AC_GETGRENT_R_GNU
   _X_AC_GETGRENT_R_SUN
+  CFLAGS="${_x_ac_getgrent_cflags_save}"
+  ac_c_werror_flag="${_x_ac_getgrent_werror_save}"
 ])
 
+AC_DEFUN([_X_AC_GETGRENT_CHECK_WNO_IMPLICIT], [
+  AC_MSG_CHECKING([if ${CC} supports -Wno-implicit-function-declaration])
+  _x_ac_getgrent_check_cflags_save="${CFLAGS}"
+  CFLAGS="${CFLAGS} -Wno-implicit-function-declaration -Werror"
+  AC_COMPILE_IFELSE(
+    [AC_LANG_PROGRAM()],
+    [ x_ac_getgrent_have_wno_implicit=yes
+      x_ac_getgrent_wno_implicit_flag="-Wno-implicit-function-declaration" ],
+    [ x_ac_getgrent_have_wno_implicit=no
+      x_ac_getgrent_wno_implicit_flag="" ]
+  )
+  CFLAGS="${_x_ac_getgrent_check_cflags_save}"
+  AS_IF(
+    [test "x${x_ac_getgrent_have_wno_implicit}" = xyes],
+    [AC_MSG_RESULT([yes])],
+    [AC_MSG_RESULT([no])]
+  )]
+)
+
 AC_DEFUN([_X_AC_GETGRENT_R_AIX], [
   AC_CACHE_CHECK(
     [for getgrent_r (AIX)],
     [x_ac_cv_have_getgrent_r_aix], [
-    _x_ac_getgrent_r_aix_c_werror_flag="$ac_c_werror_flag"
-    ac_c_werror_flag=yes
     AC_LINK_IFELSE([
       AC_LANG_PROGRAM([[
 #define _THREAD_SAFE 1
@@ -44,8 +68,7 @@
       )],
       AS_VAR_SET(x_ac_cv_have_getgrent_r_aix, yes),
       AS_VAR_SET(x_ac_cv_have_getgrent_r_aix, no)
-    )
-    ac_c_werror_flag="$_x_ac_getgrent_r_aix_c_werror_flag"]
+    )]
   )
   AS_IF([test AS_VAR_GET(x_ac_cv_have_getgrent_r_aix) = yes],
     AC_DEFINE([HAVE_GETGRENT_R_AIX], [1],
@@ -58,8 +81,6 @@
   AC_CACHE_CHECK(
     [for getgrent_r (GNU)],
     [x_ac_cv_have_getgrent_r_gnu], [
-    _x_ac_getgrent_r_gnu_c_werror_flag="$ac_c_werror_flag"
-    ac_c_werror_flag=yes
     AC_LINK_IFELSE([
       AC_LANG_PROGRAM([[
 #define _GNU_SOURCE 1
@@ -73,8 +94,7 @@
       )],
       AS_VAR_SET(x_ac_cv_have_getgrent_r_gnu, yes),
       AS_VAR_SET(x_ac_cv_have_getgrent_r_gnu, no)
-    )
-    ac_c_werror_flag="$_x_ac_getgrent_r_gnu_c_werror_flag"]
+    )]
   )
   AS_IF([test AS_VAR_GET(x_ac_cv_have_getgrent_r_gnu) = yes],
     AC_DEFINE([HAVE_GETGRENT_R_GNU], [1],
@@ -87,8 +107,6 @@
   AC_CACHE_CHECK(
     [for getgrent_r (SunOS)],
     [x_ac_cv_have_getgrent_r_sun], [
-    _x_ac_getgrent_r_sun_c_werror_flag="$ac_c_werror_flag"
-    ac_c_werror_flag=yes
     AC_LINK_IFELSE([
       AC_LANG_PROGRAM([[
 #include <grp.h>
@@ -100,8 +118,7 @@
       )],
       AS_VAR_SET(x_ac_cv_have_getgrent_r_sun, yes),
       AS_VAR_SET(x_ac_cv_have_getgrent_r_sun, no)
-    )
-    ac_c_werror_flag="$_x_ac_getgrent_r_sun_c_werror_flag"]
+    )]
   )
   AS_IF([test AS_VAR_GET(x_ac_cv_have_getgrent_r_sun) = yes],
     AC_DEFINE([HAVE_GETGRENT_R_SUN], [1],