From 7cacde3b84e170326c49eb950dfd6222e40dbf50 Mon Sep 17 00:00:00 2001
From: Dimitri Schoolwerth <dimitri@schoolwerth.com>
Date: Sun, 31 May 2015 03:08:17 +0400
Subject: [PATCH] Re-enable symbols visibility support for the Clang compiler

Visibility support for Clang was disabled in 7198c33 because of linking
errors when building shared libraries, related to non-inline methods in
exported template classes.

The last Clang version to have these problems is version "4.1
(tags/Apple/clang-421.11.66)" as part of Xcode 4.5.2, and the next
release fixes them (version "4.2 (clang-425.0.24)", Xcode 4.6). Check
for the Clang version and only disable visibility support when compiling
with Apple Clang < 4.2.

Note that Apple Clang 4.2 is based on official Clang 3.2 so also check
for that version in case of non-Apple builds. The only official Clang
that has been tested successfully is 3.4 which worked fine with
visibility. Other versions that were tried (3.1 and 3.2) segfault while
compiling wx.
---
 build/aclocal/visibility.m4 | 19 ++++++++++++++++---
 configure                   | 19 ++++++++++++++++---
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/build/aclocal/visibility.m4 b/build/aclocal/visibility.m4
index 05f9b80dec..3d7c972aec 100644
--- a/build/aclocal/visibility.m4
+++ b/build/aclocal/visibility.m4
@@ -49,9 +49,22 @@ AC_DEFUN([WX_VISIBILITY],
          error this platform has no visibility;
          #endif
 
-         /* at the time of Xcode 4.1 / Clang 3, Clang++ still didn't have the bugs sorted out: */
-         #if defined(__clang__)
-         clang compiler is still broken w.r.t. visibility;
+         /* At the time of Xcode 4.1 / Clang 3, Clang++ still didn't
+            have the bugs sorted out. These were fixed starting with
+            Xcode 4.6.0 / Apple Clang 4.2 (which is based on Clang 3.2 so
+            check for that version too). */
+         #ifdef __clang__
+            #ifdef __APPLE__
+                #if __clang_major__ < 4 \
+                    || (__clang_major__ == 4 && __clang_minor__ < 2)
+                    error Clang compiler version < 4.2 is broken w.r.t. visibility;
+                #endif
+            #else
+                #if __clang_major__ < 3 \
+                    || (__clang_major__ == 3 && __clang_minor__ < 2)
+                    error Clang compiler version < 3.2 is broken w.r.t. visibility;
+                #endif
+            #endif
          #endif
 
          extern __attribute__((__visibility__("hidden"))) int hiddenvar;
diff --git a/configure b/configure
index a9ea1093da..8ca1986e7f 100755
--- a/configure
+++ b/configure
@@ -28921,9 +28921,22 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
          error this platform has no visibility;
          #endif
 
-         /* at the time of Xcode 4.1 / Clang 3, Clang++ still didn't have the bugs sorted out: */
-         #if defined(__clang__)
-         clang compiler is still broken w.r.t. visibility;
+         /* At the time of Xcode 4.1 / Clang 3, Clang++ still didn't
+            have the bugs sorted out. These were fixed starting with
+            Xcode 4.6.0 / Apple Clang 4.2 (which is based on Clang 3.2 so
+            check for that version too). */
+         #ifdef __clang__
+            #ifdef __APPLE__
+                #if __clang_major__ < 4 \
+                    || (__clang_major__ == 4 && __clang_minor__ < 2)
+                    error Clang compiler version < 4.2 is broken w.r.t. visibility;
+                #endif
+            #else
+                #if __clang_major__ < 3 \
+                    || (__clang_major__ == 3 && __clang_minor__ < 2)
+                    error Clang compiler version < 3.2 is broken w.r.t. visibility;
+                #endif
+            #endif
          #endif
 
          extern __attribute__((__visibility__("hidden"))) int hiddenvar;