Adjust configure so that it sets CFLAGS properly for Intel's icc

even if the compiler is not defining __GNUC__.  Per report from
Dirk Tilger that it is possible for icc to not do that.

configure

@@ -2818,6 +2818,58 @@ ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
+# Check if it's Intel's compiler, which (usually) pretends to be gcc,
+# but has idiosyncrasies of its own.  We assume icc will define
+# __INTEL_COMPILER regardless of CFLAGS.
+
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+int
+main ()
+{
+#ifndef __INTEL_COMPILER
+choke me
+#endif
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+  (eval $ac_compile) 2>conftest.er1
+  ac_status=$?
+  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_objext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ICC=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ICC=no
+fi
+rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+
 unset CFLAGS
 
 #
@@ -2846,12 +2898,15 @@ fi
 
 # Some versions of GCC support some additional useful warning flags.
 # Check whether they are supported, and add them to CFLAGS if so.
-
-if test "$GCC" = yes; then
-
 # ICC pretends to be GCC but it's lying; it doesn't support these options.
-# So we have to check if "GCC" is really ICC.
 
+if test "$GCC" = yes -a "$ICC" = no; then
+  CFLAGS="$CFLAGS -Wall -Wmissing-prototypes -Wpointer-arith -Winline"
+  # These work in some but not all gcc versions
+  echo "$as_me:$LINENO: checking if $CC supports -Wdeclaration-after-statement" >&5
+echo $ECHO_N "checking if $CC supports -Wdeclaration-after-statement... $ECHO_C" >&6
+pgac_save_CFLAGS=$CFLAGS
+CFLAGS="$pgac_save_CFLAGS -Wdeclaration-after-statement"
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -2862,9 +2917,7 @@ cat >>conftest.$ac_ext <<_ACEOF
 int
 main ()
 {
-#ifndef __INTEL_COMPILER
-choke me
-#endif
+
   ;
   return 0;
 }
@@ -2891,22 +2944,22 @@ if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ICC=yes
+  echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6
 else
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-ICC=no
+CFLAGS="$pgac_save_CFLAGS"
+                    echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
 
-  if test "$ICC" = no; then
-    CFLAGS="$CFLAGS -Wall -Wmissing-prototypes -Wpointer-arith -Winline"
-
-    echo "$as_me:$LINENO: checking if $CC supports -Wdeclaration-after-statement" >&5
-echo $ECHO_N "checking if $CC supports -Wdeclaration-after-statement... $ECHO_C" >&6
+  echo "$as_me:$LINENO: checking if $CC supports -Wendif-labels" >&5
+echo $ECHO_N "checking if $CC supports -Wendif-labels... $ECHO_C" >&6
 pgac_save_CFLAGS=$CFLAGS
-CFLAGS="$pgac_save_CFLAGS -Wdeclaration-after-statement"
+CFLAGS="$pgac_save_CFLAGS -Wendif-labels"
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -2956,10 +3009,11 @@ echo "${ECHO_T}no" >&6
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
 
-    echo "$as_me:$LINENO: checking if $CC supports -Wendif-labels" >&5
-echo $ECHO_N "checking if $CC supports -Wendif-labels... $ECHO_C" >&6
+  # Disable strict-aliasing rules; needed for gcc 3.3+
+  echo "$as_me:$LINENO: checking if $CC supports -fno-strict-aliasing" >&5
+echo $ECHO_N "checking if $CC supports -fno-strict-aliasing... $ECHO_C" >&6
 pgac_save_CFLAGS=$CFLAGS
-CFLAGS="$pgac_save_CFLAGS -Wendif-labels"
+CFLAGS="$pgac_save_CFLAGS -fno-strict-aliasing"
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -3009,11 +3063,10 @@ echo "${ECHO_T}no" >&6
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
 
-  else
-    # Intel compiler has a bug/misoptimization in checking for
-    # division by NAN (NaN == 0), -mp1 fixes it, so add it to the
-    # CFLAGS.
-    echo "$as_me:$LINENO: checking if $CC supports -mp1" >&5
+elif test "$ICC" = yes; then
+  # Intel's compiler has a bug/misoptimization in checking for
+  # division by NAN (NaN == 0), -mp1 fixes it, so add it to the CFLAGS.
+  echo "$as_me:$LINENO: checking if $CC supports -mp1" >&5
 echo $ECHO_N "checking if $CC supports -mp1... $ECHO_C" >&6
 pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -mp1"
@@ -3066,9 +3119,7 @@ echo "${ECHO_T}no" >&6
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
 
-  fi
-
-  # Disable strict-aliasing rules; needed for gcc 3.3+
+  # Not clear if this is needed, but seems like a good idea
   echo "$as_me:$LINENO: checking if $CC supports -fno-strict-aliasing" >&5
 echo $ECHO_N "checking if $CC supports -fno-strict-aliasing... $ECHO_C" >&6
 pgac_save_CFLAGS=$CFLAGS

configure.in

 dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.522 2007/07/19 17:15:30 tgl Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.523 2007/08/05 15:43:00 tgl Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -243,6 +243,13 @@ esac
 
 AC_PROG_CC([$pgac_cc_list])
 
+# Check if it's Intel's compiler, which (usually) pretends to be gcc,
+# but has idiosyncrasies of its own.  We assume icc will define
+# __INTEL_COMPILER regardless of CFLAGS.
+AC_TRY_COMPILE([], [@%:@ifndef __INTEL_COMPILER
+choke me
+@%:@endif], [ICC=[yes]], [ICC=[no]])
+
 unset CFLAGS
 
 #
@@ -271,29 +278,21 @@ fi
 
 # Some versions of GCC support some additional useful warning flags.
 # Check whether they are supported, and add them to CFLAGS if so.
-
-if test "$GCC" = yes; then
-
 # ICC pretends to be GCC but it's lying; it doesn't support these options.
-# So we have to check if "GCC" is really ICC.
-AC_TRY_COMPILE([], [@%:@ifndef __INTEL_COMPILER
-choke me
-@%:@endif], [ICC=[yes]], [ICC=[no]])
-
-  if test "$ICC" = no; then
-    CFLAGS="$CFLAGS -Wall -Wmissing-prototypes -Wpointer-arith -Winline"
-
-    PGAC_PROG_CC_CFLAGS_OPT([-Wdeclaration-after-statement])
-    PGAC_PROG_CC_CFLAGS_OPT([-Wendif-labels])
-  else
-    # Intel compiler has a bug/misoptimization in checking for
-    # division by NAN (NaN == 0), -mp1 fixes it, so add it to the
-    # CFLAGS.
-    PGAC_PROG_CC_CFLAGS_OPT([-mp1])
-  fi
 
+if test "$GCC" = yes -a "$ICC" = no; then
+  CFLAGS="$CFLAGS -Wall -Wmissing-prototypes -Wpointer-arith -Winline"
+  # These work in some but not all gcc versions
+  PGAC_PROG_CC_CFLAGS_OPT([-Wdeclaration-after-statement])
+  PGAC_PROG_CC_CFLAGS_OPT([-Wendif-labels])
   # Disable strict-aliasing rules; needed for gcc 3.3+
   PGAC_PROG_CC_CFLAGS_OPT([-fno-strict-aliasing])
+elif test "$ICC" = yes; then
+  # Intel's compiler has a bug/misoptimization in checking for
+  # division by NAN (NaN == 0), -mp1 fixes it, so add it to the CFLAGS.
+  PGAC_PROG_CC_CFLAGS_OPT([-mp1])
+  # Not clear if this is needed, but seems like a good idea
+  PGAC_PROG_CC_CFLAGS_OPT([-fno-strict-aliasing])
 elif test x"${CC}" = x"xlc"; then
   # AIX xlc has to have strict aliasing turned off too
   PGAC_PROG_CC_CFLAGS_OPT([-qnoansialias])