[telepathy-qt4/master] Use -fvisibility=hidden for telepathy-qt4 main library

[Simon McVittie]

No public symbols disappear as a result; the following command
(which assumes a 32-bit platform, but is easy to adapt) gives
identical output before and after.

nm libtelepathy-qt4.so | c++filt | sort -k3| sed -e 's/^........ //'
---
 TelepathyQt4/Makefile.am |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/TelepathyQt4/Makefile.am b/TelepathyQt4/Makefile.am
index 384d2b3..a623ec7 100644
--- a/TelepathyQt4/Makefile.am
+++ b/TelepathyQt4/Makefile.am
@@ -380,7 +380,8 @@ AM_CPPFLAGS = \
     $(QTNETWORK_CFLAGS)
 
 AM_CXXFLAGS = \
-    $(ERROR_CXXFLAGS)
+    $(ERROR_CXXFLAGS) \
+    $(VISIBILITY_HIDDEN_FLAGS)
 
 ALL_LIBS = \
     $(QTCORE_LIBS) \
-- 
1.5.6.5