commit 14f81bc47a4c462ccc609fce74feb014185e2bf9
Author: Sam James <sam@gentoo.org>
Date:   Thu Feb 9 23:17:53 2023 +0000

    ITS#10011 build: fix compatibility with stricter C99 compilers
    
    Fix the following warnings:
    - -Wimplicit-int (fatal with Clang 16)
    - -Wimplicit-function-declaration (fatal with Clang 16)
    - -Wincompatible-function-pointer-types (fatal with Clang 16)
    - -Wint-conversion (fatal with Clang 15)
    - Old style prototypes (K&R, removed from C23)
    
    These warnings-now-error led to misconfigurations and failure to build
    OpenLDAP, as the tests used during configure caused the wrong results
    to be emitted.
    
    For more information, see LWN.net [0] or LLVM's Discourse [1], the Gentoo wiki [2],
    or the (new) c-std-porting mailing list [3].
    
    [0] https://lwn.net/Articles/913505/
    [1] https://discourse.llvm.org/t/configure-script-breakage-with-the-new-werror-implicit-function-declaration/65213
    [2] https://wiki.gentoo.org/wiki/Modern_C_porting
    [3] hosted at lists.linux.dev.
    
    Bug: https://bugs.gentoo.org/871288
    Signed-off-by: Sam James <sam@gentoo.org>

diff -ur openldap-2.6.4.orig/openldap-2.6.4/build/openldap.m4 openldap-2.6.4/openldap-2.6.4/build/openldap.m4
--- openldap-2.6.4.orig/openldap-2.6.4/build/openldap.m4	2023-02-08 19:53:35.000000000 +0100
+++ openldap-2.6.4/openldap-2.6.4/build/openldap.m4	2023-04-15 19:21:07.377380382 +0200
@@ -154,6 +154,7 @@
 if test $ol_cv_header_stdc = yes; then
   # /bin/cc in Irix-4.0.5 gets non-ANSI ctype macros unless using -ansi.
 AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <ctype.h>
+#include <stdlib.h>
 #ifndef HAVE_EBCDIC
 #	define ISLOWER(c) ('a' <= (c) && (c) <= 'z')
 #	define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
@@ -303,8 +304,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -360,9 +365,13 @@
 AC_DEFUN([OL_PTHREAD_TEST_PROGRAM],
 [AC_LANG_SOURCE([OL_PTHREAD_TEST_INCLUDES
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 OL_PTHREAD_TEST_FUNCTION
 }
@@ -484,7 +493,7 @@
 #include <sys/types.h>
 #include <regex.h>
 static char *pattern, *string;
-main()
+int main(void)
 {
 	int rc;
 	regex_t re;
@@ -511,7 +520,8 @@
 [AC_CACHE_CHECK([if toupper() requires islower()],ol_cv_c_upper_lower,[
 	AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <ctype.h>
-main()
+#include <stdlib.h>
+int main(void)
 {
 	if ('C' == toupper('C'))
 		exit(0);
@@ -569,7 +579,7 @@
 			]])],[ol_cv_nonposix_strerror_r=yes],[ol_cv_nonposix_strerror_r=no])
 	else
 		AC_RUN_IFELSE([AC_LANG_SOURCE([[
-			main() {
+			int main(void) {
 				char buf[100];
 				buf[0] = 0;
 				strerror_r( 1, buf, sizeof buf );
diff -ur openldap-2.6.4.orig/openldap-2.6.4/configure openldap-2.6.4/openldap-2.6.4/configure
--- openldap-2.6.4.orig/openldap-2.6.4/configure	2023-02-08 19:53:35.000000000 +0100
+++ openldap-2.6.4/openldap-2.6.4/configure	2023-04-15 19:23:17.437078213 +0200
@@ -14978,6 +14966,7 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <ctype.h>
+#include <stdlib.h>
 #ifndef HAVE_EBCDIC
 #	define ISLOWER(c) ('a' <= (c) && (c) <= 'z')
 #	define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
@@ -15946,6 +15935,10 @@
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
+#include <stdlib.h>
+#ifdef HAVE_SYS_POLL_H
+#include <sys/epoll.h>
+#endif
 int main(int argc, char **argv)
 {
 	int epfd = epoll_create(256);
@@ -16126,7 +16119,7 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
-			main() {
+			int main(void) {
 				char buf[100];
 				buf[0] = 0;
 				strerror_r( 1, buf, sizeof buf );
@@ -16326,7 +16319,7 @@
 #include <sys/types.h>
 #include <regex.h>
 static char *pattern, *string;
-main()
+int main(void)
 {
 	int rc;
 	regex_t re;
@@ -17559,16 +17552,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -17664,8 +17665,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -17744,16 +17749,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -17854,8 +17867,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -17934,16 +17951,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -18044,8 +18069,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -18124,16 +18153,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -18234,8 +18271,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -18314,16 +18355,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -18424,8 +18473,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -18504,16 +18557,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -18615,8 +18676,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -18695,16 +18760,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -18805,8 +18878,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -18885,16 +18962,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -18996,8 +19081,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -19076,16 +19165,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -19187,8 +19284,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -19267,16 +19368,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -19377,8 +19486,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -19457,16 +19570,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -19568,8 +19689,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -19648,16 +19773,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -19759,8 +19892,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -19839,16 +19976,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -19949,8 +20094,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -20029,16 +20178,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -20139,8 +20296,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -20219,16 +20380,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -20330,8 +20499,12 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
@@ -20410,16 +20583,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -20631,14 +20812,12 @@
 /* end confdefs.h.  */
 
 #include <pthread.h>
-#ifndef NULL
-#define NULL (void*)0
-#endif
+pthread_t thread;
 
 int
 main ()
 {
-pthread_detach(NULL);
+pthread_detach(thread);
   ;
   return 0;
 }
@@ -20752,16 +20931,24 @@
 #define NULL (void*)0
 #endif
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	return (void *) (p == NULL);
 }
 
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 
 	/* pthread test function */
@@ -20851,6 +21038,9 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
+#define _XOPEN_SOURCE 500               /* For pthread_setconcurrency() on glibc */
+#include <stdlib.h>
+#include <stdio.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <unistd.h>
@@ -20861,8 +21051,12 @@
 
 static int fildes[2];
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	int i;
 	struct timeval tv;
@@ -20886,9 +21080,13 @@
 	exit(0); /* if we exit here, the select blocked the whole process */
 }
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 	pthread_t t;
 
@@ -23241,7 +23439,8 @@
 /* end confdefs.h.  */
 
 #include <ctype.h>
-main()
+#include <stdlib.h>
+int main(void)
 {
 	if ('C' == toupper('C'))
 		exit(0);
diff -ur openldap-2.6.4.orig/openldap-2.6.4/configure.ac openldap-2.6.4/openldap-2.6.4/configure.ac
--- openldap-2.6.4.orig/openldap-2.6.4/configure.ac	2023-02-08 19:53:35.000000000 +0100
+++ openldap-2.6.4/openldap-2.6.4/configure.ac	2023-04-15 19:21:07.377380382 +0200
@@ -1003,7 +1003,11 @@
 AC_CHECK_HEADERS( sys/epoll.h )
 if test "${ac_cv_header_sys_epoll_h}" = yes; then
 	AC_MSG_CHECKING(for epoll system call)
-	AC_RUN_IFELSE([AC_LANG_SOURCE([[int main(int argc, char **argv)
+	AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <stdlib.h>
+#ifdef HAVE_SYS_POLL_H
+#include <sys/epoll.h>
+#endif
+int main(int argc, char **argv)
 {
 	int epfd = epoll_create(256);
 	exit (epfd == -1 ? 1 : 0);
@@ -1356,10 +1360,10 @@
 		dnl 	pthread_create() in -lpthread (many)
 		dnl 	pthread_create() in -lc_r (FreeBSD)
 		dnl
-		dnl Check pthread (draft4) flags (depreciated)
+		dnl Check pthread (draft4) flags (deprecated)
 		dnl 	pthread_create() with -threads (OSF/1)
 		dnl
-		dnl Check pthread (draft4) libraries (depreciated)
+		dnl Check pthread (draft4) libraries (deprecated)
 		dnl 	pthread_mutex_unlock() in -lpthreads -lmach -lexc -lc_r (OSF/1)
 		dnl 	pthread_mutex_lock() in -lpthreads -lmach -lexc (OSF/1)
 		dnl 	pthread_mutex_trylock() in -lpthreads -lexc (OSF/1)
@@ -1378,7 +1382,7 @@
 			ol_link_threads=posix
 			ol_link_pthreads=""
 		fi
-		
+
 dnl		OL_PTHREAD_TRY([-mt],		[ol_cv_pthread_mt])
 		OL_PTHREAD_TRY([-kthread],	[ol_cv_pthread_kthread])
 		OL_PTHREAD_TRY([-pthread],	[ol_cv_pthread_pthread])
@@ -1465,10 +1469,8 @@
 				dnl save the flags
 				AC_LINK_IFELSE([AC_LANG_PROGRAM([[
 #include <pthread.h>
-#ifndef NULL
-#define NULL (void*)0
-#endif
-]], [[pthread_detach(NULL);]])],[ol_cv_func_pthread_detach=yes],[ol_cv_func_pthread_detach=no])
+pthread_t thread;
+]], [[pthread_detach(thread);]])],[ol_cv_func_pthread_detach=yes],[ol_cv_func_pthread_detach=no])
 			])
 
 			if test $ol_cv_func_pthread_detach = no ; then
@@ -1523,6 +1525,9 @@
 				AC_CACHE_CHECK([if select yields when using pthreads],
 					ol_cv_pthread_select_yields,[
 				AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#define _XOPEN_SOURCE 500               /* For pthread_setconcurrency() on glibc */
+#include <stdlib.h>
+#include <stdio.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <unistd.h>
@@ -1533,8 +1538,12 @@
 
 static int fildes[2];
 
+#ifdef __STDC__
+static void *task(void *p)
+#else
 static void *task(p)
 	void *p;
+#endif
 {
 	int i;
 	struct timeval tv;
@@ -1558,9 +1567,13 @@
 	exit(0); /* if we exit here, the select blocked the whole process */
 }
 
+#ifdef __STDC__
+int main(int argc, char **argv)
+#else
 int main(argc, argv)
 	int argc;
 	char **argv;
+#endif
 {
 	pthread_t t;