From 9ea223df2dc4fb30821334d3265c484efcc0dd57 Mon Sep 17 00:00:00 2001
From: "Field G. Van Zee" <field@cs.utexas.edu>
Date: Fri, 15 Mar 2019 13:57:49 -0500
Subject: [PATCH] Use -fvisibility=[...] with clang on Linux/BSD/OSX.

Details:
- Modified common.mk to use the -fvisibility=[hidden|default] option
  when compiling with clang on non-Windows platforms (Linux, BSD, OS X,
  etc.). Thanks to Isuru Fernando for pointing out this option works
  with clang on these OSes.
---
 common.mk | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/common.mk b/common.mk
index 3326d2acd..9a63bd0aa 100644
--- a/common.mk
+++ b/common.mk
@@ -643,6 +643,8 @@ endif
 endif
 
 # Determine default export behavior / visibility of symbols for icc.
+# NOTE: The Windows branches have been omitted since we currently make no
+# effort to support Windows builds via icc (only gcc/clang via AppVeyor).
 ifeq ($(CC_VENDOR),icc)
 ifeq ($(ENABLE_EXPORT_ALL),yes)
 # Export all symbols by default.
@@ -669,13 +671,12 @@ CMISCFLAGS :=
 endif
 else # ifeq ($(IS_WIN),no)
 ifeq ($(ENABLE_EXPORT_ALL),yes)
-# NOTE: Not sure if clang on Linux/BSD/OSX supports exporting all symbols by
-# default.
-CMISCFLAGS :=
+# Export all symbols by default.
+CMISCFLAGS := -fvisibility=default
 else
-# NOTE: Not sure if clang on Linux/BSD/OSX supports hiding all symbols by
-# default.
-CMISCFLAGS :=
+# Hide all symbols by default and export only those that have been annotated
+# as needing to be exported.
+CMISCFLAGS := -fvisibility=hidden
 endif
 endif
 endif