Remove duplicate flags from configure output.

Upstream commit 2c5d6f1f (Lane "Include $cc_string in the info
reported by a configure run.") has moved the compiler flags output
section down but we most likely mismerged it during 9.2 merge (commit
598f4b0e "Merge with PostgreSQL 9.2beta2.")

To keep behavior parity we're keeping the LIBS output line here. This
seems actually still useful, and if we later find it less valuable it
should be trivial to take it out.

Before:

checking whether ccache clang-10 supports -Wl,--as-needed... (cached) yes
checking whether ccache clang-10 supports -Werror=uninitialized... (cached) yes
checking whether ccache clang-10 supports -Werror=implicit-function-declaration... (cached) yes
configure: using CFLAGS=-Wall -Wmissing-prototypes -Wpointer-arith -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -Wno-unused-command-line-argument -g -ggdb -O3 -std=gnu99  -Werror=uninitialized -Werror=implicit-function-declaration
configure: using CPPFLAGS= -D_GNU_SOURCE
configure: using LDFLAGS=-fuse-ld=lld  -Wl,--as-needed
configure: using LIBS=-lxerces-c -lbz2 -lrt -lssl -lcrypto -lzstd -lz -lreadline -lrt -lcrypt -ldl -lm
configure: using compiler=clang version 10.0.0-++20200412073924+50d7e5d5e7d-1~exp1~20200412054519.133
configure: using CFLAGS=-Wall -Wmissing-prototypes -Wpointer-arith -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -Wno-unused-command-line-argument -g -ggdb -O3 -std=gnu99  -Werror=uninitialized -Werror=implicit-function-declaration
configure: using CPPFLAGS= -D_GNU_SOURCE
configure: using LDFLAGS=-fuse-ld=lld  -Wl,--as-needed
configure: creating ./config.status

After:

checking whether ccache clang-10 supports -Wl,--as-needed... (cached) yes
checking whether ccache clang-10 supports -Werror=uninitialized... (cached) yes
checking whether ccache clang-10 supports -Werror=implicit-function-declaration... (cached) yes
configure: using compiler=clang version 10.0.0-++20200412073924+50d7e5d5e7d-1~exp1~20200412054519.133
configure: using CFLAGS=-Wall -Wmissing-prototypes -Wpointer-arith -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -Wno-unused-command-line-argument -g -ggdb -O3 -std=gnu99  -Werror=uninitialized -Werror=implicit-function-declaration
configure: using CPPFLAGS= -D_GNU_SOURCE  -I/home/pivotal/.opt/xerces/include
configure: using LDFLAGS=-fuse-ld=lld  -L/home/pivotal/.opt/xerces/lib -Wl,--as-needed
configure: creating ./config.status

configure

@@ -19514,17 +19514,6 @@ fi
 
 fi
 
-# Begin output steps
-
-{ $as_echo "$as_me:${as_lineno-$LINENO}: using CFLAGS=$CFLAGS" >&5
-$as_echo "$as_me: using CFLAGS=$CFLAGS" >&6;}
-{ $as_echo "$as_me:${as_lineno-$LINENO}: using CPPFLAGS=$CPPFLAGS" >&5
-$as_echo "$as_me: using CPPFLAGS=$CPPFLAGS" >&6;}
-{ $as_echo "$as_me:${as_lineno-$LINENO}: using LDFLAGS=$LDFLAGS" >&5
-$as_echo "$as_me: using LDFLAGS=$LDFLAGS" >&6;}
-{ $as_echo "$as_me:${as_lineno-$LINENO}: using LIBS=$LIBS" >&5
-$as_echo "$as_me: using LIBS=$LIBS" >&6;}
-
 BLD_ARCH=`echo $BLD_ARCH`
 
 
@@ -19631,6 +19620,8 @@ $as_echo "$as_me: using CFLAGS=$CFLAGS" >&6;}
 $as_echo "$as_me: using CPPFLAGS=$CPPFLAGS" >&6;}
 { $as_echo "$as_me:${as_lineno-$LINENO}: using LDFLAGS=$LDFLAGS" >&5
 $as_echo "$as_me: using LDFLAGS=$LDFLAGS" >&6;}
+{ $as_echo "$as_me:${as_lineno-$LINENO}: using LIBS=$LIBS" >&5
+$as_echo "$as_me: using LIBS=$LIBS" >&6;}
 
 # prepare build tree if outside source tree
 # Note 1: test -ef might not exist, but it's more reliable than `pwd`.

configure.in

@@ -2762,13 +2762,6 @@ if test "$GCC" = yes -a "$ICC" = no; then
   PGAC_PROG_CC_CFLAGS_OPT([-Werror=implicit-function-declaration])
 fi
 
-# Begin output steps
-
-AC_MSG_NOTICE([using CFLAGS=$CFLAGS])
-AC_MSG_NOTICE([using CPPFLAGS=$CPPFLAGS])
-AC_MSG_NOTICE([using LDFLAGS=$LDFLAGS])
-AC_MSG_NOTICE([using LIBS=$LIBS])
-
 [BLD_ARCH=`echo $BLD_ARCH`]
 AC_SUBST(BLD_ARCH)
 
@@ -2855,6 +2848,7 @@ AC_MSG_NOTICE([using compiler=$cc_string])
 AC_MSG_NOTICE([using CFLAGS=$CFLAGS])
 AC_MSG_NOTICE([using CPPFLAGS=$CPPFLAGS])
 AC_MSG_NOTICE([using LDFLAGS=$LDFLAGS])
+AC_MSG_NOTICE([using LIBS=$LIBS])
 
 # prepare build tree if outside source tree
 # Note 1: test -ef might not exist, but it's more reliable than `pwd`.