macOS build: Fix 'direct access in function...' warning

For every executable that uses a static Qt library (e.g. rcc using
libQt5Bootstrap.a) we got a warning: 'direct access in function...to
global weak symbol'.

This was because we've built all libraries with -fvisibility=hidden
-fvisibility-inlines-hidden but not the executables linking against
them. On macOS however, all translation units must have the same
visibility setting.

We're now setting the same visibilty for libs and executables on
darwin.

Fixes: QTBUG-81297
Change-Id: I2668e9385caa7f0ce78bf3727b4e5322bc4a294f
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

mkspecs/features/qt_common.prf

@@ -23,7 +23,6 @@ qtConfig(c11): CONFIG += c11
 qtConfig(stack-protector-strong): CONFIG += stack_protector_strong
 contains(TEMPLATE, .*lib) {
     # module and plugins
-    if(!host_build|!cross_compile):qtConfig(reduce_exports): CONFIG += hide_symbols
     unix:qtConfig(reduce_relocations): CONFIG += bsymbolic_functions
     qtConfig(separate_debug_info): CONFIG += separate_debug_info
 
@@ -58,6 +57,9 @@ contains(TEMPLATE, .*lib) {
         QMAKE_PRL_INSTALL_REPLACE += qtlibdir_replace
     }
 }
+contains(TEMPLATE, .*lib)|darwin {
+    if(!host_build|!cross_compile):qtConfig(reduce_exports): CONFIG += hide_symbols
+}
 
 # The remainder of this file must not apply to host tools/libraries,
 # as the host compiler's version and capabilities are not checked.