[Enh 2959069] Support for -fvisibility=hidden

2 files changed, 73 insertions, 9 deletions

diff --git a/unix/configure b/unix/configure
index eeaeb8c..382c284 100755
--- a/unix/configure
+++ b/unix/configure
@@ -4315,6 +4315,62 @@ if test "${tcl_cv_cc_visibility_hidden+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
 
+	hold_cflags=$CFLAGS; CFLAGS="$CFLAGS -fvisibility=hidden"
+	cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$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 $ac_status); }; }; then
+  tcl_cv_cc_visibility_hidden=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+tcl_cv_cc_visibility_hidden=no
+fi
+rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+	CFLAGS=$hold_cflags
+fi
+echo "$as_me:$LINENO: result: $tcl_cv_cc_visibility_hidden" >&5
+echo "${ECHO_T}$tcl_cv_cc_visibility_hidden" >&6
+    if test $tcl_cv_cc_visibility_hidden = yes; then
+
+	CFLAGS="$CFLAGS -fvisibility=hidden"
+
+else
+
 	hold_cflags=$CFLAGS; CFLAGS="$CFLAGS -Werror"
 	cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
@@ -4365,10 +4421,7 @@ fi
 rm -f conftest.err conftest.$ac_objext \
       conftest$ac_exeext conftest.$ac_ext
 	CFLAGS=$hold_cflags
-fi
-echo "$as_me:$LINENO: result: $tcl_cv_cc_visibility_hidden" >&5
-echo "${ECHO_T}$tcl_cv_cc_visibility_hidden" >&6
-    if test $tcl_cv_cc_visibility_hidden = yes; then
+	if test $tcl_cv_cc_visibility_hidden = yes; then
 
 
 cat >>confdefs.h <<\_ACEOF
@@ -4379,6 +4432,9 @@ _ACEOF
 fi
 
 
+fi
+
+
     # Step 0.d: Disable -rpath support?
 
     echo "$as_me:$LINENO: checking if rpath support is requested" >&5
diff --git a/unix/tcl.m4 b/unix/tcl.m4
index 34a06bd..c5045c7 100644
--- a/unix/tcl.m4
+++ b/unix/tcl.m4
@@ -1052,16 +1052,24 @@ AC_DEFUN([SC_CONFIG_CFLAGS], [
 
     AC_CACHE_CHECK([if compiler supports visibility "hidden"],
 	tcl_cv_cc_visibility_hidden, [
+	hold_cflags=$CFLAGS; CFLAGS="$CFLAGS -fvisibility=hidden"
+	AC_TRY_COMPILE(,, tcl_cv_cc_visibility_hidden=yes,
+	    tcl_cv_cc_visibility_hidden=no)
+	CFLAGS=$hold_cflags])
+    AS_IF([test $tcl_cv_cc_visibility_hidden = yes], [
+	CFLAGS="$CFLAGS -fvisibility=hidden"
+    ], [
 	hold_cflags=$CFLAGS; CFLAGS="$CFLAGS -Werror"
 	AC_TRY_LINK([
 	    extern __attribute__((__visibility__("hidden"))) void f(void);
 	    void f(void) {}], [f();], tcl_cv_cc_visibility_hidden=yes,
 	    tcl_cv_cc_visibility_hidden=no)
-	CFLAGS=$hold_cflags])
-    AS_IF([test $tcl_cv_cc_visibility_hidden = yes], [
-	AC_DEFINE(MODULE_SCOPE,
-	    [extern __attribute__((__visibility__("hidden")))],
-	    [Compiler support for module scope symbols])
+	CFLAGS=$hold_cflags
+	AS_IF([test $tcl_cv_cc_visibility_hidden = yes], [
+	    AC_DEFINE(MODULE_SCOPE,
+		[extern __attribute__((__visibility__("hidden")))],
+		[Compiler support for module scope symbols])
+	])
     ])
 
     # Step 0.d: Disable -rpath support?