Add GCC >= gcc 4 support for default hidden/explicit public

[awithers]

Submitted largely so people can look it over and make me not commit it.

This patch adds a new --enable-symbol-visibility switch to configure which turns on use_hidesyms which selectively turns on -fvisibility=hidden (currently selectively because only libmyth and libmythtv are close to done, external libs will never be done).

Objectives:

Smaller symbol tables An explicit API

Deficiencies:

Only the symbols I absolutely needed plus reasonable guesses are here (basically most of the stuff that would be exposed through mythtv/ includes). If you use this patch and find some I missed let me know.

[awithers]

(In [11469]) References #2421

First of n patches to get explicit symbol visibility in myth (for use with newer gcc).

If you do not enable it, this should only make you rebuild everything. To enable it you must run configure with --enable-symbol-visibility.

This commit introduces the new mythpluginapi.h. The purpose of this header is to provide prototypes for the plugin entry points (previously every plugin prototyped them). Existing plugins should include this file (I'll be updating them soon).

If you enable this, expect to find symbols I've somehow missed, report them.

Why? Cleaner, smaller, tables. Everyone likes clean tables.

[awithers]

(In [11470]) References #2421

Update to use explicit symbol visibility changes.

[greg]

(In [11540])

Updates mythgame to use explicity symbol visibility changes

recently commited.

references #2421

[anonymous]

getting follwing after this commit....

../../libs/libmythui/libmythui-0.20.so: undefined reference to `JoystickMenuClient::Init(QString&)' ../../libs/libmythui/libmythui-0.20.so: undefined reference to `JoystickMenuClient::JoystickMenuClient?(QObject*)' ../../libs/libmythui/libmythui-0.20.so: undefined reference to `JoystickMenuClient::Process()'

[awithers]

(In [12854]) References #2421

Export ClearChannelLocks? for hidden symbols patch.

[awithers]

(In [13050]) References #2421

• Export GetInstallPrefixPath?
• Slide in -pedantic fix while I'm here

[awithers]

(In [13163]) References #2421

export ViewScheduleDiff?

[awithers]

(In [14201]) References #2421

Export ThemeInfo?

[awithers]

(In [15454]) References #2421

Mark InputGroupMap? as public, for --enable-symbol-visibility.

[awithers]

(In [15823]) References #2421

Export ChannelTVFormat for GetFormats?().

[awithers]

(In [16740]) References #2421

Exports AudioSettings? for --enable-symbol-visibility.

[awithers]

(In [17695]) References #2421

Exports new MDBManager and MSocketDevice.

With thanks to Michael T. Dean for the reminder.

[awithers]

(In [19073]) References #2421

Don't export a few things that are now only referenced inside libmythui, adds libmythui to those supporting --enable-symbol-visibility.

[awithers]

(In [19355]) References #2421

symbol visibility update

[awithers]

(In [19420]) References #2421

Export PlayerContex? and MythApplication?.

[awithers]

(In [19839]) References #2421

Export MythUIFileBrowser.

[awithers]

(In [19984]) References #2421

decodeencode.cpp is discovering things about itself and liking what it finds.

[awithers]

(In [20007]) References #2421

[stuartm]

Anduin, is this unfinished or can the ticket now be closed?

[awithers]

(In [23019]) References #2421

Fix build when --enable-symbol-visibility is used.

[stuarta]

We've done lots of symbol visibility fixes. We can deal with any new ones on a case by case basis.