r22731: - Fix bug #4594.

  configure.in determines if -Werror-implicit-function-declaration is
  available, and if so it enables that flag if --enable-developer is
  specified.  Since the configure tests themselves did not use that flag, it
  was possible for a configure test to succeed, followed by a failed
  compilation due to a facility being available but not having a proper
  declaration in a header file.  (This bit me with readahead().)  This patch
  ensures that if implicit function declarations will kill the build, the
  feature being tested is deselected so the build will succeed.

  The autoconf manual suggests using return instead of exit in configure
  tests because the declaration for exit is often missing.  We require this
  now, since we error if prototypes are missing.  See section 5.5.1 of
  http://www.gnu.org/software/autoconf/manual/autoconf.html.  This patch makes
  these changes, because in fact, an external declaration for exit is missing
  here (and likely elsewhere).

  I've verified that the features selected (here) with the original
  configure.in and the new one are the same except for, in my case,
  readahead.  I've also confirmed that the generated Makefile is identical.

  These changes are not being applied to the 3.0.26 branch because it does not
  exhibit the initial problem this patch is supposed to solve since it doesn't
  attempt to use -Werror-implicit-function-declaration.
(This used to be commit 4d42720915b8f65842147171f689127e94d1b973)

1 files changed, 92 insertions, 66 deletions

diff --git a/source3/configure.in b/source3/configure.in
index 19f0a2e511..497c4ac624 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -412,6 +412,7 @@ AC_ARG_ENABLE(developer, [  --enable-developer      Turn on developer warnings a
 	    samba_cv_HAVE_Wdeclaration_after_statement=yes,
 	    samba_cv_HAVE_Wdeclaration_after_statement=no,
 	    samba_cv_HAVE_Wdeclaration_after_statement=cross)
+
        ])
        if test x"$samba_cv_HAVE_Wdeclaration_after_statement" = x"yes"; then
 	    DEVELOPER_CFLAGS="${DEVELOPER_CFLAGS} -Wdeclaration-after-statement"
@@ -807,11 +808,11 @@ case "$host_os" in
         CPPFLAGS="-D_LARGEFILE64_SOURCE $CPPFLAGS"
         AC_TRY_RUN([
 #include <unistd.h>
-main () {
+int main () {
 #if _LFS64_LARGEFILE == 1
-exit(0);
+return 0;
 #else
-exit(1);
+return 1;
 #endif
 }], [SINIX_LFS_SUPPORT=yes], [SINIX_LFS_SUPPORT=no], [SINIX_LFS_SUPPORT=cross])
         CPPFLAGS="$old_CPPFLAGS"
@@ -846,7 +847,7 @@ exit(1);
 #include <sys/utsname.h>
 #include <string.h>
 #include <stdlib.h>
-main() {
+int main() {
 #if _LFS64_LARGEFILE == 1
        struct utsname uts;
        char *release;
@@ -858,9 +859,9 @@ main() {
        int libc_minor = __GLIBC_MINOR__;
 
        if (libc_major < 2)
-              exit(1);
+              return 1;
        if (libc_minor < 2)
-              exit(1);
+              return 1;
 #endif
 
        /* Ensure this is kernel 2.4 or higher */
@@ -871,10 +872,10 @@ main() {
        minor = atoi(strsep(&release, "."));
 
        if (major > 2 || (major == 2 && minor > 3))
-               exit(0);
-       exit(1);
+               return 0;
+       return 1;
 #else
-       exit(1);
+       return 1;
 #endif
 }
 ], [LINUX_LFS_SUPPORT=yes], [LINUX_LFS_SUPPORT=no], [LINUX_LFS_SUPPORT=cross])
@@ -907,9 +908,9 @@ main() {
 #include <unistd.h>
 main () {
 #if _LFS64_LARGEFILE == 1
-exit(0);
+return 0;
 #else
-exit(1);
+return 1;
 #endif
 }], [GLIBC_LFS_SUPPORT=yes], [GLIBC_LFS_SUPPORT=no], [GLIBC_LFS_SUPPORT=cross])
         CPPFLAGS="$old_CPPFLAGS"
@@ -1161,7 +1162,7 @@ AC_HAVE_DECL(snprintf, [#include <stdio.h>])
 # nothing until kernel 2.1.44! very dumb.
 AC_CACHE_CHECK([for real setresuid],samba_cv_have_setresuid,[
     AC_TRY_RUN([#include <errno.h>
-main() { setresuid(1,1,1); setresuid(2,2,2); exit(errno==EPERM?0:1);}],
+int main() { setresuid(1,1,1); setresuid(2,2,2); return errno==EPERM?0:1;}],
 	samba_cv_have_setresuid=yes,samba_cv_have_setresuid=no,samba_cv_have_setresuid=cross)])
 if test x"$samba_cv_have_setresuid" = x"yes"; then
     AC_DEFINE(HAVE_SETRESUID,1,[Whether the system has setresuid])
@@ -1172,7 +1173,7 @@ fi
 AC_CACHE_CHECK([for real setresgid],samba_cv_have_setresgid,[
     AC_TRY_RUN([#include <unistd.h>
 #include <errno.h>
-main() { errno = 0; setresgid(1,1,1); exit(errno != 0 ? (errno==EPERM ? 0 : 1) : 0);}],
+int main() { errno = 0; setresgid(1,1,1); return errno != 0 ? (errno==EPERM ? 0 : 1) : 0;}],
 	samba_cv_have_setresgid=yes,samba_cv_have_setresgid=no,samba_cv_have_setresgid=cross)])
 if test x"$samba_cv_have_setresgid" = x"yes"; then
     AC_DEFINE(HAVE_SETRESGID,1,[Whether the system has setresgid])
@@ -1332,6 +1333,23 @@ AC_CHECK_HEADERS(execinfo.h libexc.h libunwind.h)
 AC_CHECK_FUNCS(backtrace_symbols)
 AC_CHECK_LIB(exc, trace_back_stack)
 
+# Save the original CFLAGS for a few tests that we want to allow
+# implicit declaration warnings without failing the test (in developer mode)
+ac_no_error_on_warning_CFLAGS="${CFLAGS}"
+
+# Since --enable-developer causes warnings to be treated as errors during
+# compilation, we should avoid using features that will fail to compile.
+#
+# We don't want to enable this earlier because the built-in functions such as
+# memset fail to configure properly.
+
+if test x"$samba_cv_HAVE_Werror_implicit_function_declaration" = x"yes" -a \
+        x"$developer" = xyes; then
+  CFLAGS="${CFLAGS} -Werror-implicit-function-declaration"
+  ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+  ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+fi
+
 echo -n "checking for GPFS GPL libs... "
 save_LIBS="$LIBS"
 LIBS="$LIBS -lgpfs_gpl"
@@ -1467,18 +1485,18 @@ case "$host_os" in
 #include <unistd.h>
 #include <sys/utsname.h>
 
-		    main() {
+		    int main() {
 			   /* glibc up to 2.3 has a broken getgrouplist */
 #if defined(__GLIBC__) && defined(__GLIBC_MINOR__)
 			   int libc_major = __GLIBC__;
 			   int libc_minor = __GLIBC_MINOR__;
 
 			   if (libc_major < 2)
-				  exit(1);
+				  return 1;
 			   if ((libc_major == 2) && (libc_minor <= 3))
-				  exit(1);
+				  return 1;
 #endif
-			   exit(0);
+			   return 0;
 		    }
 
 		],
@@ -1507,7 +1525,7 @@ if test x$ac_cv_func_stat64 = xno ; then
 #include <unistd.h>
 #endif
 #include <sys/stat.h>
-], [struct stat64 st64; exit(stat64(".",&st64));], [ac_cv_func_stat64=yes])
+], [struct stat64 st64; return stat64(".",&st64);], [ac_cv_func_stat64=yes])
   AC_MSG_RESULT([$ac_cv_func_stat64])
   if test x$ac_cv_func_stat64 = xyes ; then
     AC_DEFINE(HAVE_STAT64,1,[Whether stat64() is available])
@@ -1521,7 +1539,7 @@ if test x$ac_cv_func_lstat64 = xno ; then
 #include <unistd.h>
 #endif
 #include <sys/stat.h>
-], [struct stat64 st64; exit(lstat64(".",&st64));], [ac_cv_func_lstat64=yes])
+], [struct stat64 st64; return lstat64(".",&st64);], [ac_cv_func_lstat64=yes])
   AC_MSG_RESULT([$ac_cv_func_lstat64])
   if test x$ac_cv_func_lstat64 = xyes ; then
     AC_DEFINE(HAVE_LSTAT64,[Whether lstat64() is available])
@@ -1535,7 +1553,7 @@ if test x$ac_cv_func_fstat64 = xno ; then
 #include <unistd.h>
 #endif
 #include <sys/stat.h>
-], [struct stat64 st64; exit(fstat64(0,&st64));], [ac_cv_func_fstat64=yes])
+], [struct stat64 st64; return fstat64(0,&st64);], [ac_cv_func_fstat64=yes])
   AC_MSG_RESULT([$ac_cv_func_fstat64])
   if test x$ac_cv_func_fstat64 = xyes ; then
     AC_DEFINE(HAVE_FSTAT64,1,[Whether fstat64() is available])
@@ -2021,7 +2039,7 @@ AC_DEFINE_UNQUOTED(SHLIBEXT, "$SHLIBEXT", [Shared library extension])
 
 AC_CACHE_CHECK([for long long],samba_cv_have_longlong,[
 AC_TRY_RUN([#include <stdio.h>
-main() { long long x = 1000000; x *= x; exit(((x/1000000) == 1000000)? 0: 1); }],
+int main() { long long x = 1000000; x *= x; return ((x/1000000) == 1000000)? 0: 1; }],
 samba_cv_have_longlong=yes,samba_cv_have_longlong=no,samba_cv_have_longlong=cross)])
 if test x"$samba_cv_have_longlong" = x"yes"; then
     AC_DEFINE(HAVE_LONGLONG,1,[Whether the host supports long long's])
@@ -2045,7 +2063,7 @@ fi
 AC_CACHE_CHECK([for 64 bit off_t],samba_cv_SIZEOF_OFF_T,[
 AC_TRY_RUN([#include <stdio.h>
 #include <sys/stat.h>
-main() { exit((sizeof(off_t) == 8) ? 0 : 1); }],
+int main() { return (sizeof(off_t) == 8) ? 0 : 1; }],
 samba_cv_SIZEOF_OFF_T=yes,samba_cv_SIZEOF_OFF_T=no,samba_cv_SIZEOF_OFF_T=cross)])
 if test x"$samba_cv_SIZEOF_OFF_T" = x"yes"; then
     AC_DEFINE(SIZEOF_OFF_T,8,[The size of the 'off_t' type])
@@ -2058,7 +2076,7 @@ AC_TRY_RUN([
 #endif
 #include <stdio.h>
 #include <sys/stat.h>
-main() { struct stat64 st; off64_t s; if (sizeof(off_t) == sizeof(off64_t)) exit(1); exit((lstat64("/dev/null", &st)==0)?0:1); }],
+int main() { struct stat64 st; off64_t s; if (sizeof(off_t) == sizeof(off64_t)) return 1; return (lstat64("/dev/null", &st)==0)?0:1; }],
 samba_cv_HAVE_OFF64_T=yes,samba_cv_HAVE_OFF64_T=no,samba_cv_HAVE_OFF64_T=cross)])
 if test x"$samba_cv_HAVE_OFF64_T" = x"yes"; then
     AC_DEFINE(HAVE_OFF64_T,1,[Whether off64_t is available])
@@ -2071,7 +2089,7 @@ AC_TRY_RUN([
 #endif
 #include <stdio.h>
 #include <sys/stat.h>
-main() { exit((sizeof(ino_t) == 8) ? 0 : 1); }],
+int main() { return (sizeof(ino_t) == 8) ? 0 : 1; }],
 samba_cv_SIZEOF_INO_T=yes,samba_cv_SIZEOF_INO_T=no,samba_cv_SIZEOF_INO_T=cross)])
 if test x"$samba_cv_SIZEOF_INO_T" = x"yes"; then
     AC_DEFINE(SIZEOF_INO_T,8,[The size of the 'ino_t' type])
@@ -2084,7 +2102,7 @@ AC_TRY_RUN([
 #endif
 #include <stdio.h>
 #include <sys/stat.h>
-main() { struct stat64 st; ino64_t s; if (sizeof(ino_t) == sizeof(ino64_t)) exit(1); exit((lstat64("/dev/null", &st)==0)?0:1); }],
+int main() { struct stat64 st; ino64_t s; if (sizeof(ino_t) == sizeof(ino64_t)) return 1; return (lstat64("/dev/null", &st)==0)?0:1; }],
 samba_cv_HAVE_INO64_T=yes,samba_cv_HAVE_INO64_T=no,samba_cv_HAVE_INO64_T=cross)])
 if test x"$samba_cv_HAVE_INO64_T" = x"yes"; then
     AC_DEFINE(HAVE_INO64_T,1,[Whether the 'ino64_t' type is available])
@@ -2097,7 +2115,7 @@ AC_TRY_RUN([
 #endif
 #include <stdio.h>
 #include <sys/stat.h>
-main() { exit((sizeof(dev_t) == 8) ? 0 : 1); }],
+int main() { return (sizeof(dev_t) == 8) ? 0 : 1; }],
 samba_cv_SIZEOF_DEV_T=yes,samba_cv_SIZEOF_DEV_T=no,samba_cv_SIZEOF_DEV_T=cross)])
 if test x"$samba_cv_SIZEOF_DEV_T" = x"yes"; then
     AC_DEFINE(SIZEOF_DEV_T,8,[The size of the 'dev_t' type])
@@ -2110,7 +2128,7 @@ AC_TRY_RUN([
 #endif
 #include <stdio.h>
 #include <sys/stat.h>
-main() { struct stat64 st; dev64_t s; if (sizeof(dev_t) == sizeof(dev64_t)) exit(1); exit((lstat64("/dev/null", &st)==0)?0:1); }],
+int main() { struct stat64 st; dev64_t s; if (sizeof(dev_t) == sizeof(dev64_t)) return 1; return (lstat64("/dev/null", &st)==0)?0:1; }],
 samba_cv_HAVE_DEV64_T=yes,samba_cv_HAVE_DEV64_T=no,samba_cv_HAVE_DEV64_T=cross)])
 if test x"$samba_cv_HAVE_DEV64_T" = x"yes"; then
     AC_DEFINE(HAVE_DEV64_T,1,[Whether the 'dev64_t' type is available])
@@ -2148,7 +2166,7 @@ AC_TRY_RUN([
 #include <unistd.h>
 #endif
 #include <sys/types.h>
-main() { dev_t dev; int i = major(dev); return 0; }],
+int main() { dev_t dev; int i = major(dev); return 0; }],
 samba_cv_HAVE_DEVICE_MAJOR_FN=yes,samba_cv_HAVE_DEVICE_MAJOR_FN=no,samba_cv_HAVE_DEVICE_MAJOR_FN=cross)])
 if test x"$samba_cv_HAVE_DEVICE_MAJOR_FN" = x"yes"; then
     AC_DEFINE(HAVE_DEVICE_MAJOR_FN,1,[Whether the major macro for dev_t is available])
@@ -2160,7 +2178,7 @@ AC_TRY_RUN([
 #include <unistd.h>
 #endif
 #include <sys/types.h>
-main() { dev_t dev; int i = minor(dev); return 0; }],
+int main() { dev_t dev; int i = minor(dev); return 0; }],
 samba_cv_HAVE_DEVICE_MINOR_FN=yes,samba_cv_HAVE_DEVICE_MINOR_FN=no,samba_cv_HAVE_DEVICE_MINOR_FN=cross)])
 if test x"$samba_cv_HAVE_DEVICE_MINOR_FN" = x"yes"; then
     AC_DEFINE(HAVE_DEVICE_MINOR_FN,1,[Whether the minor macro for dev_t is available])
@@ -2172,7 +2190,7 @@ AC_TRY_RUN([
 #include <unistd.h>
 #endif
 #include <sys/types.h>
-main() { dev_t dev = makedev(1,2); return 0; }],
+int main() { dev_t dev = makedev(1,2); return 0; }],
 samba_cv_HAVE_MAKEDEV=yes,samba_cv_HAVE_MAKEDEV=no,samba_cv_HAVE_MAKEDEV=cross)])
 if test x"$samba_cv_HAVE_MAKEDEV" = x"yes"; then
     AC_DEFINE(HAVE_MAKEDEV,1,[Whether the macro for makedev is available])
@@ -2180,7 +2198,7 @@ fi
 
 AC_CACHE_CHECK([for unsigned char],samba_cv_HAVE_UNSIGNED_CHAR,[
 AC_TRY_RUN([#include <stdio.h>
-main() { char c; c=250; exit((c > 0)?0:1); }],
+int main() { char c; c=250; return (c > 0)?0:1; }],
 samba_cv_HAVE_UNSIGNED_CHAR=yes,samba_cv_HAVE_UNSIGNED_CHAR=no,samba_cv_HAVE_UNSIGNED_CHAR=cross)])
 if test x"$samba_cv_HAVE_UNSIGNED_CHAR" = x"yes"; then
     AC_DEFINE(HAVE_UNSIGNED_CHAR,1,[Whether the 'unsigned char' type is available])
@@ -2216,7 +2234,7 @@ AC_CACHE_CHECK([if gettimeofday takes tz argument],samba_cv_HAVE_GETTIMEOFDAY_TZ
 AC_TRY_RUN([
 #include <sys/time.h>
 #include <unistd.h>
-main() { struct timeval tv; exit(gettimeofday(&tv, NULL));}],
+int main() { struct timeval tv; return gettimeofday(&tv, NULL);}],
            samba_cv_HAVE_GETTIMEOFDAY_TZ=yes,samba_cv_HAVE_GETTIMEOFDAY_TZ=no,samba_cv_HAVE_GETTIMEOFDAY_TZ=cross)])
 if test x"$samba_cv_HAVE_GETTIMEOFDAY_TZ" = x"yes"; then
     AC_DEFINE(HAVE_GETTIMEOFDAY_TZ,1,[Whether gettimeofday() is available])
@@ -2270,18 +2288,18 @@ void foo(const char *format, ...) {
        va_start(ap, format);
        len = vsnprintf(buf, 0, format, ap);
        va_end(ap);
-       if (len != 5) exit(1);
+       if (len != 5) return 1;
 
        va_start(ap, format);
        len = vsnprintf(0, 0, format, ap);
        va_end(ap);
-       if (len != 5) exit(1);
+       if (len != 5) return 1;
 
-       if (snprintf(buf, 3, "hello") != 5 || strcmp(buf, "he") != 0) exit(1);
+       if (snprintf(buf, 3, "hello") != 5 || strcmp(buf, "he") != 0) return 1;
 
-       exit(0);
+       return 0;
 }
-main() { foo("hello"); }
+int main() { foo("hello"); }
 ],
 samba_cv_HAVE_C99_VSNPRINTF=yes,samba_cv_HAVE_C99_VSNPRINTF=no,samba_cv_HAVE_C99_VSNPRINTF=cross)])
 if test x"$samba_cv_HAVE_C99_VSNPRINTF" = x"yes"; then
@@ -2291,9 +2309,9 @@ fi
 AC_CACHE_CHECK([for broken readdir name],samba_cv_HAVE_BROKEN_READDIR_NAME,[
 AC_TRY_RUN([#include <sys/types.h>
 #include <dirent.h>
-main() { struct dirent *di; DIR *d = opendir("."); di = readdir(d);
+int main() { struct dirent *di; DIR *d = opendir("."); di = readdir(d);
 if (di && di->d_name[-2] == '.' && di->d_name[-1] == 0 &&
-di->d_name[0] == 0) exit(0); exit(1);} ],
+di->d_name[0] == 0) return 0; return 1;} ],
 samba_cv_HAVE_BROKEN_READDIR_NAME=yes,samba_cv_HAVE_BROKEN_READDIR_NAME=no,samba_cv_HAVE_BROKEN_READDIR_NAME=cross)])
 if test x"$samba_cv_HAVE_BROKEN_READDIR_NAME" = x"yes"; then
     AC_DEFINE(HAVE_BROKEN_READDIR_NAME,1,[Whether readdir() returns the wrong name offset])
@@ -2302,7 +2320,7 @@ fi
 AC_CACHE_CHECK([for utimbuf],samba_cv_HAVE_UTIMBUF,[
 AC_TRY_COMPILE([#include <sys/types.h>
 #include <utime.h>],
-[struct utimbuf tbuf;  tbuf.actime = 0; tbuf.modtime = 1; exit(utime("foo.c",&tbuf));],
+[struct utimbuf tbuf;  tbuf.actime = 0; tbuf.modtime = 1; return utime("foo.c",&tbuf);],
 samba_cv_HAVE_UTIMBUF=yes,samba_cv_HAVE_UTIMBUF=no,samba_cv_HAVE_UTIMBUF=cross)])
 if test x"$samba_cv_HAVE_UTIMBUF" = x"yes"; then
     AC_DEFINE(HAVE_UTIMBUF,1,[Whether struct utimbuf is available])
@@ -2591,7 +2609,7 @@ AC_TRY_RUN([
 #ifndef F_GETLEASE
 #define F_GETLEASE	1025
 #endif
-main() {
+int main() {
        int fd = open("/dev/null", O_RDONLY);
        return fcntl(fd, F_GETLEASE, 0) == -1;
 }
@@ -2609,8 +2627,8 @@ AC_TRY_RUN([
 #ifndef F_NOTIFY
 #define F_NOTIFY 1026
 #endif
-main() {
-       	exit(fcntl(open("/tmp", O_RDONLY), F_NOTIFY, 0) == -1 ?  1 : 0);
+int main() {
+       	return fcntl(open("/tmp", O_RDONLY), F_NOTIFY, 0) == -1 ?  1 : 0;
 }
 ],
 samba_cv_HAVE_KERNEL_CHANGE_NOTIFY=yes,samba_cv_HAVE_KERNEL_CHANGE_NOTIFY=no,samba_cv_HAVE_KERNEL_CHANGE_NOTIFY=cross)])
@@ -2685,8 +2703,8 @@ AC_TRY_RUN([
 #define LOCK_MAND	32
 #define LOCK_READ	64
 #endif
-main() {
-       	exit(flock(open("/dev/null", O_RDWR), LOCK_MAND|LOCK_READ) != 0);
+int main() {
+       	return flock(open("/dev/null", O_RDWR), LOCK_MAND|LOCK_READ) != 0;
 }
 ],
 samba_cv_HAVE_KERNEL_SHARE_MODES=yes,samba_cv_HAVE_KERNEL_SHARE_MODES=no,samba_cv_HAVE_KERNEL_SHARE_MODES=cross)])
@@ -2722,15 +2740,15 @@ if test x"$samba_cv_HAVE_SYS_CAPABILITY_H" = x"yes"; then
 		AC_TRY_RUN([
 #include <sys/types.h>
 #include <sys/capability.h>
-main() {
+int main() {
  cap_t cap;
  cap_value_t vals[1];
  if (!(cap = cap_get_proc()))
-   exit(1);
+   return 1;
  vals[0] = CAP_CHOWN;
  cap_set_flag(cap, CAP_INHERITABLE, 1, vals, CAP_CLEAR);
  cap_set_proc(cap);
- exit(0);
+ return 0;
 }],
 		samba_cv_HAVE_POSIX_CAPABILITIES=yes,
 		samba_cv_HAVE_POSIX_CAPABILITIES=no,
@@ -2852,15 +2870,15 @@ AC_TRY_RUN([#include <stdlib.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
-main() {
+int main() {
   struct stat st;
   char tpl[20]="/tmp/test.XXXXXX";
   int fd = mkstemp(tpl);
-  if (fd == -1) exit(1);
+  if (fd == -1) return 1;
   unlink(tpl);
-  if (fstat(fd, &st) != 0) exit(1);
-  if ((st.st_mode & 0777) != 0600) exit(1);
-  exit(0);
+  if (fstat(fd, &st) != 0) return 1;
+  if ((st.st_mode & 0777) != 0600) return 1;
+  return 0;
 }],
 samba_cv_HAVE_SECURE_MKSTEMP=yes,
 samba_cv_HAVE_SECURE_MKSTEMP=no,
@@ -3048,11 +3066,11 @@ dnl
 #ifdef HAVE_SYS_FCNTL_H
 #include <sys/fcntl.h>
 #endif
-main() { struct flock64 fl64;
+int main() { struct flock64 fl64;
 #if defined(F_SETLKW64) && defined(F_SETLK64) && defined(F_GETLK64)
-exit(0);
+return 0;
 #else
-exit(1);
+return 1;
 #endif
 }],
        samba_cv_HAVE_STRUCT_FLOCK64=yes,samba_cv_HAVE_STRUCT_FLOCK64=no,samba_cv_HAVE_STRUCT_FLOCK64=cross)])
@@ -3133,10 +3151,11 @@ fi
 AC_CACHE_CHECK([if the realpath function allows a NULL argument],samba_cv_REALPATH_TAKES_NULL,[
 AC_TRY_RUN([
 #include <stdio.h>
+#include <stdlib.h>
 #include <limits.h>
-main() {
+int main() {
 	char *newpath = realpath("/tmp", NULL);
-	exit ((newpath != NULL) ? 0 : 1);
+	return (newpath != NULL) ? 0 : 1;
 }
 ],
 samba_cv_REALPATH_TAKES_NULL=yes,samba_cv_REALPATH_TAKES_NULL=no,samba_cv_REALPATH_TAKES_NULL=cross)])
@@ -3980,7 +3999,7 @@ if test x"$with_ads_support" != x"no"; then
                 samba_cv_HAVE_WRFILE_KEYTAB,[
     AC_TRY_RUN([
 #include<krb5.h>
-  main()
+  int main()
   {
     krb5_context context;
     krb5_keytab keytab;
@@ -4722,6 +4741,8 @@ if test x"$samba_cv_SYSQUOTA_FOUND" != x"no"; then
 AC_CACHE_CHECK([whether the sys_quota interface works],samba_cv_SYSQUOTA_WORKS,[
 SAVE_CPPFLAGS="$CPPFLAGS"
 CPPFLAGS="$CPPFLAGS ${SAMBA_CONFIGURE_CPPFLAGS}"
+SAVE_CFLAGS="$CFLAGS"
+CFLAGS="${ac_no_error_on_warning_CFLAGS}"
 AC_TRY_COMPILE([
 #include "confdefs.h"
 #define NO_PROTO_H 1
@@ -4731,6 +4752,7 @@ AC_TRY_COMPILE([
 #include "${srcdir-.}/lib/sysquotas.c"
 ],[],samba_cv_SYSQUOTA_WORKS=yes,samba_cv_SYSQUOTA_WORKS=no)
 CPPFLAGS="$SAVE_CPPFLAGS"
+CFLAGS="$SAVE_CFLAGS"
 ])
 if test x"$samba_cv_SYSQUOTA_WORKS" = x"yes"; then
 AC_MSG_CHECKING(whether to use the new lib/sysquotas.c interface)
@@ -4769,6 +4791,8 @@ fi
 AC_CACHE_CHECK([whether the old quota support works],samba_cv_QUOTA_WORKS,[
 SAVE_CPPFLAGS="$CPPFLAGS"
 CPPFLAGS="$CPPFLAGS ${SAMBA_CONFIGURE_CPPFLAGS}"
+SAVE_CFLAGS="$CFLAGS"
+CFLAGS="${ac_no_error_on_warning_CFLAGS}"
 AC_TRY_COMPILE([
 #include "confdefs.h"
 #define NO_PROTO_H 1
@@ -4776,6 +4800,7 @@ AC_TRY_COMPILE([
 #include "${srcdir-.}/smbd/quotas.c"
 ],[],samba_cv_QUOTA_WORKS=yes,samba_cv_QUOTA_WORKS=no)
 CPPFLAGS="$SAVE_CPPFLAGS"
+CFLAGS="$SAVE_CFLAGS"
 ])
 if test x"$samba_cv_QUOTA_WORKS" = x"yes"; then
 AC_MSG_CHECKING(whether to use the old quota support)
@@ -5042,7 +5067,7 @@ if test $space = no; then
   main ()
   {
     struct statvfs64 fsd;
-    exit (statvfs64 (".", &fsd));
+    return statvfs64 (".", &fsd);
   }],
   fu_cv_sys_stat_statvfs64=yes,
   fu_cv_sys_stat_statvfs64=no,
@@ -5095,7 +5120,7 @@ if test $space = no; then
   {
     struct statfs fsd;
     fsd.f_fsize = 0;
-    exit (statfs (".", &fsd, sizeof (struct statfs)));
+    return statfs (".", &fsd, sizeof (struct statfs));
   }],
   fu_cv_sys_stat_statfs3_osf1=yes,
   fu_cv_sys_stat_statfs3_osf1=no,
@@ -5126,7 +5151,7 @@ member (AIX, 4.3BSD)])
   {
   struct statfs fsd;
   fsd.f_bsize = 0;
-  exit (statfs (".", &fsd));
+  return statfs (".", &fsd);
   }],
   fu_cv_sys_stat_statfs2_bsize=yes,
   fu_cv_sys_stat_statfs2_bsize=no,
@@ -5147,7 +5172,7 @@ if test $space = no; then
   main ()
   {
   struct statfs fsd;
-  exit (statfs (".", &fsd, sizeof fsd, 0));
+  return statfs (".", &fsd, sizeof fsd, 0);
   }],
     fu_cv_sys_stat_statfs4=yes,
     fu_cv_sys_stat_statfs4=no,
@@ -5175,7 +5200,7 @@ member (4.4BSD and NetBSD)])
   {
   struct statfs fsd;
   fsd.f_fsize = 0;
-  exit (statfs (".", &fsd));
+  return statfs (".", &fsd);
   }],
   fu_cv_sys_stat_statfs2_fsize=yes,
   fu_cv_sys_stat_statfs2_fsize=no,
@@ -5206,7 +5231,7 @@ if test $space = no; then
   struct fs_data fsd;
   /* Ultrix's statfs returns 1 for success,
      0 for not mounted, -1 for failure.  */
-  exit (statfs (".", &fsd) != 1);
+  return statfs (".", &fsd) != 1;
   }],
   fu_cv_sys_stat_fs_data=yes,
   fu_cv_sys_stat_fs_data=no,
@@ -5801,6 +5826,7 @@ samba_cv_HAVE_SENDFILE=yes,samba_cv_HAVE_SENDFILE=no)])
 
 AC_CACHE_CHECK([for Linux readahead],
                 samba_cv_HAVE_LINUX_READAHEAD,[
+
     AC_TRY_LINK([
 #if defined(HAVE_UNISTD_H)
 #include <unistd.h>
@@ -6364,7 +6390,7 @@ AC_TRY_RUN([#include "${srcdir-.}/tests/summary.c"],
 
 dnl Merge in developer cflags from now on
 if test x"$developer" = x"yes"; then
-    CFLAGS="${CFLAGS} ${DEVELOPER_CFLAGS}"
+    CFLAGS="${ac_no_error_on_warning_CFLAGS} ${DEVELOPER_CFLAGS}"
 fi
 
 builddir=`pwd`