diff --git a/configure b/configure
index 5aff38ce984..4fb66501733 100755
--- a/configure
+++ b/configure
@@ -725,6 +725,7 @@ autodepend
 TAS
 GCC
 CPP
+CFLAGS_SL
 CFLAGS_VECTOR
 SUN_STUDIO_CC
 OBJEXT
@@ -5039,7 +5040,6 @@ fi
 
 fi
 
-CFLAGS_VECTOR=$CFLAGS_VECTOR
 
 
 # supply -g if --enable-debug
@@ -5078,6 +5078,9 @@ fi
 # the automatic additions.
 CFLAGS="$CFLAGS $user_CFLAGS"
 
+# The template file must set up CFLAGS_SL; we don't support user override
+
+
 # Check if the compiler still works with the final flag settings
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the C compiler still works" >&5
 $as_echo_n "checking whether the C compiler still works... " >&6; }
diff --git a/configure.in b/configure.in
index ffc782b44e2..61bd57e2378 100644
--- a/configure.in
+++ b/configure.in
@@ -480,7 +480,7 @@ elif test "$PORTNAME" = "hpux"; then
   PGAC_PROG_CC_CFLAGS_OPT([+Olibmerrno])
 fi
 
-AC_SUBST(CFLAGS_VECTOR, $CFLAGS_VECTOR)
+AC_SUBST(CFLAGS_VECTOR)
 
 # supply -g if --enable-debug
 if test "$enable_debug" = yes && test "$ac_cv_prog_cc_g" = yes; then
@@ -517,6 +517,9 @@ fi
 # the automatic additions.
 CFLAGS="$CFLAGS $user_CFLAGS"
 
+# The template file must set up CFLAGS_SL; we don't support user override
+AC_SUBST(CFLAGS_SL)
+
 # Check if the compiler still works with the final flag settings
 AC_MSG_CHECKING([whether the C compiler still works])
 AC_TRY_LINK([], [return 0;],
diff --git a/src/Makefile.global.in b/src/Makefile.global.in
index d5ecc16baa0..7caaf7018e1 100644
--- a/src/Makefile.global.in
+++ b/src/Makefile.global.in
@@ -240,6 +240,7 @@ CC = @CC@
 GCC = @GCC@
 SUN_STUDIO_CC = @SUN_STUDIO_CC@
 CFLAGS = @CFLAGS@
+CFLAGS_SL = @CFLAGS_SL@
 CFLAGS_VECTOR = @CFLAGS_VECTOR@
 CFLAGS_SSE42 = @CFLAGS_SSE42@
 
diff --git a/src/makefiles/Makefile.cygwin b/src/makefiles/Makefile.cygwin
index 2d57b4b0891..df22d9fd993 100644
--- a/src/makefiles/Makefile.cygwin
+++ b/src/makefiles/Makefile.cygwin
@@ -12,7 +12,6 @@ LIBS:=$(filter-out -lm -lc, $(LIBS))
 
 AROPT = crs
 DLSUFFIX = .dll
-CFLAGS_SL =
 
 override CPPFLAGS += -DWIN32_STACK_RLIMIT=$(WIN32_STACK_RLIMIT)
 
diff --git a/src/makefiles/Makefile.freebsd b/src/makefiles/Makefile.freebsd
index 5008c96b3f5..8e5bc9c6ec9 100644
--- a/src/makefiles/Makefile.freebsd
+++ b/src/makefiles/Makefile.freebsd
@@ -7,8 +7,6 @@ endif
 
 DLSUFFIX = .so
 
-CFLAGS_SL = -fPIC -DPIC
-
 # extra stuff for $(with_temp_install)
 # we need this to get LD_LIBRARY_PATH searched ahead of the compiled-in
 # rpath, if no DT_RUNPATH is present in the executable. The conditions
diff --git a/src/makefiles/Makefile.hpux b/src/makefiles/Makefile.hpux
index aef035e8463..bb76afc9b8f 100644
--- a/src/makefiles/Makefile.hpux
+++ b/src/makefiles/Makefile.hpux
@@ -37,11 +37,6 @@ ifeq ($(host_cpu), ia64)
 else
    DLSUFFIX = .sl
 endif
-ifeq ($(GCC), yes)
-   CFLAGS_SL = -fPIC
-else
-   CFLAGS_SL = +Z
-endif
 
 # env var name to use in place of LD_LIBRARY_PATH
 ld_library_path_var = SHLIB_PATH
diff --git a/src/makefiles/Makefile.linux b/src/makefiles/Makefile.linux
index f4f091caef5..c6d0546e4d5 100644
--- a/src/makefiles/Makefile.linux
+++ b/src/makefiles/Makefile.linux
@@ -7,8 +7,6 @@ rpath = -Wl,-rpath,'$(rpathdir)',--enable-new-dtags
 
 DLSUFFIX = .so
 
-CFLAGS_SL = -fPIC
-
 
 # Rule for building a shared library from a single .o file
 %.so: %.o
diff --git a/src/makefiles/Makefile.netbsd b/src/makefiles/Makefile.netbsd
index 43841c15973..c2a3cce4f01 100644
--- a/src/makefiles/Makefile.netbsd
+++ b/src/makefiles/Makefile.netbsd
@@ -9,8 +9,6 @@ endif
 
 DLSUFFIX = .so
 
-CFLAGS_SL = -fPIC -DPIC
-
 
 # Rule for building a shared library from a single .o file
 %.so: %.o
diff --git a/src/makefiles/Makefile.openbsd b/src/makefiles/Makefile.openbsd
index d8fde49d5c8..0c5a7b4eb35 100644
--- a/src/makefiles/Makefile.openbsd
+++ b/src/makefiles/Makefile.openbsd
@@ -7,8 +7,6 @@ endif
 
 DLSUFFIX = .so
 
-CFLAGS_SL = -fPIC -DPIC
-
 
 # Rule for building a shared library from a single .o file
 %.so: %.o
diff --git a/src/makefiles/Makefile.sco b/src/makefiles/Makefile.sco
index 993861570ac..49c6693f148 100644
--- a/src/makefiles/Makefile.sco
+++ b/src/makefiles/Makefile.sco
@@ -2,11 +2,7 @@ AROPT = cr
 export_dynamic = -Wl,-Bexport
 
 DLSUFFIX = .so
-ifeq ($(GCC), yes)
-CFLAGS_SL = -fpic
-else
-CFLAGS_SL = -K PIC
-endif
+
 
 # Rule for building a shared library from a single .o file
 %.so: %.o
diff --git a/src/makefiles/Makefile.solaris b/src/makefiles/Makefile.solaris
index e459de30cf4..a05c0e0d3d2 100644
--- a/src/makefiles/Makefile.solaris
+++ b/src/makefiles/Makefile.solaris
@@ -10,11 +10,7 @@ rpath = -Wl,-R'$(rpathdir)'
 endif
 
 DLSUFFIX = .so
-ifeq ($(GCC), yes)
-CFLAGS_SL = -fPIC
-else
-CFLAGS_SL = -KPIC
-endif
+
 
 # Rule for building a shared library from a single .o file
 %.so: %.o
diff --git a/src/makefiles/Makefile.unixware b/src/makefiles/Makefile.unixware
index a52717b2688..3d177b76e97 100644
--- a/src/makefiles/Makefile.unixware
+++ b/src/makefiles/Makefile.unixware
@@ -17,11 +17,7 @@ endif
 CFLAGS += $(PTHREAD_CFLAGS)
 
 DLSUFFIX = .so
-ifeq ($(GCC), yes)
-CFLAGS_SL = -fpic
-else
-CFLAGS_SL = -K PIC
-endif
+
 ifeq ($(GCC), yes)
 SO_FLAGS = -shared
 else
diff --git a/src/makefiles/Makefile.win32 b/src/makefiles/Makefile.win32
index 3c8024a715f..d02dfd2b187 100644
--- a/src/makefiles/Makefile.win32
+++ b/src/makefiles/Makefile.win32
@@ -13,7 +13,6 @@ override CPPFLAGS += -DWIN32_STACK_RLIMIT=$(WIN32_STACK_RLIMIT)
 
 AROPT = crs
 DLSUFFIX = .dll
-CFLAGS_SL =
 
 ifneq (,$(findstring backend,$(subdir)))
 ifeq (,$(findstring conversion_procs,$(subdir)))
diff --git a/src/template/aix b/src/template/aix
index 230d4613f3c..f7954123e1b 100644
--- a/src/template/aix
+++ b/src/template/aix
@@ -1,3 +1,5 @@
+# src/template/aix
+
 # Set default options if using xlc.  This formerly included -qsrcmsg, but that
 # option elicits internal compiler errors from xlc v16.1.0.  Note: configure
 # will add -qnoansialias if the compiler accepts it, even if user specifies a
@@ -13,6 +15,9 @@ if test "$GCC" != yes ; then
   esac
 fi
 
+# Extra CFLAGS for code that will go into a shared library
+CFLAGS_SL=""
+
 # Native memset() is faster, tested on:
 # 	AIX 5.1 and 5.2, XLC 6.0 (IBM's cc)
 # 	AIX 5.3 ML3, gcc 4.0.1
diff --git a/src/template/cygwin b/src/template/cygwin
index b6ea0ded522..79a108145ff 100644
--- a/src/template/cygwin
+++ b/src/template/cygwin
@@ -2,6 +2,9 @@
 
 SRCH_LIB="/usr/local/lib"
 
+# Extra CFLAGS for code that will go into a shared library
+CFLAGS_SL=""
+
 # --allow-multiple-definition is required to link pg_dump because it finds
 # pg_toupper() etc. in both libpq and pgport
 # we'd prefer to use --disable-auto-import to match MSVC linking behavior,
diff --git a/src/template/darwin b/src/template/darwin
index c05adca0bfb..f4d4e9d7cf8 100644
--- a/src/template/darwin
+++ b/src/template/darwin
@@ -16,6 +16,9 @@ if test x"$PG_SYSROOT" != x"" ; then
   fi
 fi
 
+# Extra CFLAGS for code that will go into a shared library
+CFLAGS_SL=""
+
 # Select appropriate semaphore support.  Darwin 6.0 (macOS 10.2) and up
 # support System V semaphores; before that we have to use named POSIX
 # semaphores, which are less good for our purposes because they eat a
diff --git a/src/template/freebsd b/src/template/freebsd
index 1e04fece42b..bf16e1bf072 100644
--- a/src/template/freebsd
+++ b/src/template/freebsd
@@ -1,5 +1,8 @@
 # src/template/freebsd
 
+# Extra CFLAGS for code that will go into a shared library
+CFLAGS_SL="-fPIC -DPIC"
+
 case $host_cpu in
   alpha*)   CFLAGS="-O";;  # alpha has problems with -O2
 esac
diff --git a/src/template/hpux b/src/template/hpux
index 79d3475664e..50fff80c530 100644
--- a/src/template/hpux
+++ b/src/template/hpux
@@ -8,6 +8,13 @@ if test "$GCC" != yes ; then
   CFLAGS="+O2"
 fi
 
+# Extra CFLAGS for code that will go into a shared library
+if test "$GCC" = yes ; then
+  CFLAGS_SL="-fPIC"
+else
+  CFLAGS_SL="+Z"
+fi
+
 # Pick right test-and-set (TAS) code.  We need out-of-line assembler
 # when not using gcc.
 case $host in
diff --git a/src/template/linux b/src/template/linux
index 3eb5ad2428f..09ab6af86cb 100644
--- a/src/template/linux
+++ b/src/template/linux
@@ -3,6 +3,9 @@
 # Force _GNU_SOURCE on; plperl is broken with Perl 5.8.0 otherwise
 CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE"
 
+# Extra CFLAGS for code that will go into a shared library
+CFLAGS_SL="-fPIC"
+
 # If --enable-profiling is specified, we need -DLINUX_PROFILE
 PLATFORM_PROFILE_FLAGS="-DLINUX_PROFILE"
 
diff --git a/src/template/netbsd b/src/template/netbsd
index 198697723df..d97f995c748 100644
--- a/src/template/netbsd
+++ b/src/template/netbsd
@@ -1,2 +1,5 @@
 # src/template/netbsd
 # tools/thread/thread_test must be run
+
+# Extra CFLAGS for code that will go into a shared library
+CFLAGS_SL="-fPIC -DPIC"
diff --git a/src/template/openbsd b/src/template/openbsd
index e69de29bb2d..365268c4897 100644
--- a/src/template/openbsd
+++ b/src/template/openbsd
@@ -0,0 +1,4 @@
+# src/template/openbsd
+
+# Extra CFLAGS for code that will go into a shared library
+CFLAGS_SL="-fPIC -DPIC"
diff --git a/src/template/sco b/src/template/sco
index 9a736da8be7..e216f1e7aa9 100644
--- a/src/template/sco
+++ b/src/template/sco
@@ -1 +1,10 @@
+# src/template/sco
+
 CC="$CC -b elf"
+
+# Extra CFLAGS for code that will go into a shared library
+if test "$GCC" = yes ; then
+  CFLAGS_SL="-fpic"
+else
+  CFLAGS_SL="-K PIC"
+fi
diff --git a/src/template/solaris b/src/template/solaris
index e07b9a0a8d6..f88b1cdad37 100644
--- a/src/template/solaris
+++ b/src/template/solaris
@@ -1,3 +1,12 @@
+# src/template/solaris
+
+# Extra CFLAGS for code that will go into a shared library
+if test "$GCC" = yes ; then
+  CFLAGS_SL="-fPIC"
+else
+  CFLAGS_SL="-KPIC"
+fi
+
 if test "$SUN_STUDIO_CC" = yes ; then
   CC="$CC -Xa"			# relaxed ISO C mode
   CFLAGS="-v"			# -v is like gcc -Wall
diff --git a/src/template/unixware b/src/template/unixware
index d08fca1e6be..006c4abe499 100644
--- a/src/template/unixware
+++ b/src/template/unixware
@@ -1,3 +1,5 @@
+# src/template/unixware
+
 if test "$GCC" != yes; then
   # The -Kno_host is for a bug in the compiler.  See -hackers
   # discussion on 7-8/Aug/2003.
@@ -37,5 +39,12 @@ __EOF__
 
 fi
 
+# Extra CFLAGS for code that will go into a shared library
+if test "$GCC" = yes ; then
+  CFLAGS_SL="-fpic"
+else
+  CFLAGS_SL="-K PIC"
+fi
+
 # Unixware's ldap library reportedly needs these too
 EXTRA_LDAP_LIBS="-llber -lresolv"
diff --git a/src/template/win32 b/src/template/win32
index 7da9719acbd..1380d16548c 100644
--- a/src/template/win32
+++ b/src/template/win32
@@ -1,5 +1,8 @@
 # src/template/win32
 
+# Extra CFLAGS for code that will go into a shared library
+CFLAGS_SL=""
+
 # --allow-multiple-definition is required to link pg_dump because it finds
 # pg_toupper() etc. in both libpq and pgport
 # --disable-auto-import is to ensure we get MSVC-like linking behavior