Revert to the pre-8.2 method of probing for libm, that is, always

include it if it links properly.  It seems too risky to assume that
standard functions like pow() are not special-cased by the compiler.
Per report from Andreas Lange that build fails on Solaris cc compiler
with -fast.  Even though we don't consider that a supported option,
I'm worried that similar issues will arise with other compilers.

Author: tglsfdc

configure

@@ -5038,87 +5038,32 @@ _ACEOF
 ##
 ## Libraries
 ##
+## Most libraries are included only if they demonstrably provide a function
+## we need, but libm is an exception: always include it, because there are
+## too many compilers that play cute optimization games that will break
+## probes for standard functions such as pow().
+##
 
-echo "$as_me:$LINENO: checking for library containing setproctitle" >&5
-echo $ECHO_N "checking for library containing setproctitle... $ECHO_C" >&6
-if test "${ac_cv_search_setproctitle+set}" = set; then
+
+echo "$as_me:$LINENO: checking for main in -lm" >&5
+echo $ECHO_N "checking for main in -lm... $ECHO_C" >&6
+if test "${ac_cv_lib_m_main+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
-  ac_func_search_save_LIBS=$LIBS
-ac_cv_search_setproctitle=no
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lm  $LIBS"
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 
-/* Override any gcc2 internal prototype to avoid an error.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-/* We use char because int might match the return type of a gcc2
-   builtin and then its argument prototype would still apply.  */
-char setproctitle ();
-int
-main ()
-{
-setproctitle ();
-  ;
-  return 0;
-}
-_ACEOF
-rm -f conftest.$ac_objext conftest$ac_exeext
-if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
-  (eval $ac_link) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } &&
-	 { ac_try='test -z "$ac_c_werror_flag"
-			 || test ! -s conftest.err'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; } &&
-	 { ac_try='test -s conftest$ac_exeext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  ac_cv_search_setproctitle="none required"
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
 
-fi
-rm -f conftest.err conftest.$ac_objext \
-      conftest$ac_exeext conftest.$ac_ext
-if test "$ac_cv_search_setproctitle" = no; then
-  for ac_lib in util; do
-    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
-    cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-
-/* Override any gcc2 internal prototype to avoid an error.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-/* We use char because int might match the return type of a gcc2
-   builtin and then its argument prototype would still apply.  */
-char setproctitle ();
 int
 main ()
 {
-setproctitle ();
+main ();
   ;
   return 0;
 }
@@ -5145,33 +5090,35 @@ if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ac_cv_search_setproctitle="-l$ac_lib"
-break
+  ac_cv_lib_m_main=yes
 else
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
+ac_cv_lib_m_main=no
 fi
 rm -f conftest.err conftest.$ac_objext \
       conftest$ac_exeext conftest.$ac_ext
-  done
-fi
-LIBS=$ac_func_search_save_LIBS
+LIBS=$ac_check_lib_save_LIBS
 fi
-echo "$as_me:$LINENO: result: $ac_cv_search_setproctitle" >&5
-echo "${ECHO_T}$ac_cv_search_setproctitle" >&6
-if test "$ac_cv_search_setproctitle" != no; then
-  test "$ac_cv_search_setproctitle" = "none required" || LIBS="$ac_cv_search_setproctitle $LIBS"
+echo "$as_me:$LINENO: result: $ac_cv_lib_m_main" >&5
+echo "${ECHO_T}$ac_cv_lib_m_main" >&6
+if test $ac_cv_lib_m_main = yes; then
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBM 1
+_ACEOF
+
+  LIBS="-lm $LIBS"
 
 fi
 
-echo "$as_me:$LINENO: checking for library containing pow" >&5
-echo $ECHO_N "checking for library containing pow... $ECHO_C" >&6
-if test "${ac_cv_search_pow+set}" = set; then
+echo "$as_me:$LINENO: checking for library containing setproctitle" >&5
+echo $ECHO_N "checking for library containing setproctitle... $ECHO_C" >&6
+if test "${ac_cv_search_setproctitle+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
   ac_func_search_save_LIBS=$LIBS
-ac_cv_search_pow=no
+ac_cv_search_setproctitle=no
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -5185,11 +5132,11 @@ extern "C"
 #endif
 /* We use char because int might match the return type of a gcc2
    builtin and then its argument prototype would still apply.  */
-char pow ();
+char setproctitle ();
 int
 main ()
 {
-pow ();
+setproctitle ();
   ;
   return 0;
 }
@@ -5216,16 +5163,16 @@ if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ac_cv_search_pow="none required"
+  ac_cv_search_setproctitle="none required"
 else
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
 fi
 rm -f conftest.err conftest.$ac_objext \
       conftest$ac_exeext conftest.$ac_ext
-if test "$ac_cv_search_pow" = no; then
-  for ac_lib in m; do
+if test "$ac_cv_search_setproctitle" = no; then
+  for ac_lib in util; do
     LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
     cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
@@ -5240,11 +5187,11 @@ extern "C"
 #endif
 /* We use char because int might match the return type of a gcc2
    builtin and then its argument prototype would still apply.  */
-char pow ();
+char setproctitle ();
 int
 main ()
 {
-pow ();
+setproctitle ();
   ;
   return 0;
 }
@@ -5271,7 +5218,7 @@ if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ac_cv_search_pow="-l$ac_lib"
+  ac_cv_search_setproctitle="-l$ac_lib"
 break
 else
   echo "$as_me: failed program was:" >&5
@@ -5284,10 +5231,10 @@ rm -f conftest.err conftest.$ac_objext \
 fi
 LIBS=$ac_func_search_save_LIBS
 fi
-echo "$as_me:$LINENO: result: $ac_cv_search_pow" >&5
-echo "${ECHO_T}$ac_cv_search_pow" >&6
-if test "$ac_cv_search_pow" != no; then
-  test "$ac_cv_search_pow" = "none required" || LIBS="$ac_cv_search_pow $LIBS"
+echo "$as_me:$LINENO: result: $ac_cv_search_setproctitle" >&5
+echo "${ECHO_T}$ac_cv_search_setproctitle" >&6
+if test "$ac_cv_search_setproctitle" != no; then
+  test "$ac_cv_search_setproctitle" = "none required" || LIBS="$ac_cv_search_setproctitle $LIBS"
 
 fi
 

configure.in

@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.485 2006/10/30 22:15:04 petere Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.486 2006/11/06 03:44:37 tgl Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -640,9 +640,14 @@ AC_DEFINE_UNQUOTED(PG_VERSION_NUM, $PG_VERSION_NUM, [PostgreSQL version as a num
 ##
 ## Libraries
 ##
+## Most libraries are included only if they demonstrably provide a function
+## we need, but libm is an exception: always include it, because there are
+## too many compilers that play cute optimization games that will break
+## probes for standard functions such as pow().
+##
 
+AC_CHECK_LIB(m, main)
 AC_SEARCH_LIBS(setproctitle, util)
-AC_SEARCH_LIBS(pow, m)
 AC_SEARCH_LIBS(dlopen, dl)
 AC_SEARCH_LIBS(socket, [socket wsock32])
 AC_SEARCH_LIBS(shl_load, dld)

src/include/pg_config.h.in

@@ -233,6 +233,9 @@
 /* Define to 1 if you have the `ldap_r' library (-lldap_r). */
 #undef HAVE_LIBLDAP_R
 
+/* Define to 1 if you have the `m' library (-lm). */
+#undef HAVE_LIBM
+
 /* Define to 1 if you have the `pam' library (-lpam). */
 #undef HAVE_LIBPAM