This avoids breaking plugins that don't use geanyplugin.h as they
should but include some random headers.

Whether rpath is liked or not, it allows geany to Just Work and is consistent
with autotools

The -fvisibility=hidden flag for libgeany.so is also applied to plugins.
This is not desirable.

- libgeany install dir was wrong on win32
- comdlg32 is required
- more headers need to be installed
- -fPIC is required on some platforms
- LINKFLAGS_cprogram now have to be applied to libgeany.dll

There is no need for tricking Automake to use the C++ linker to link
the main executable anymore, this is done for libgeany now.

Based on previous work from Matthew Brush.

4.2BSD sed doesn't understand the `+` quantifier, so use `{1,}`.

Instead of processing a template C source in the build system, generate
a list to be included by the preprocessor.

This simplifies the build system code as it now only generates the list
and doesn't take care of processing the template.  It incidentally
fixes build on systems with 4.2BSD sed (at least OSX and FreeBSD) as it
removes some offending sed code.

It includes stuff like -fvisibility which isn't appropriate for the main binary.

This is a bit better than compiler == 'gcc'.
Tested with gcc 4.9 (success) and gcc 3.4.5 (not supported).

In Waf, we need to add the new flags to CFLAGS *and* CXXFLAGS otherwise
the Scintilla build would break.
To keep it more reabable, we first populate a temporary list
geany_symbol_flags which is then added to CFLAGS and CXXFLAGS.

Concerning the quote FIXME: no further qoting is necessary here.

This makes it easier to define it consistently to what the compiler
and platform supports, and avoids having to include a special header
everywhere, which is some kind of a problem for separate libraries
like TagManager and especially Scintilla.

As we only use these macros from the source and not the headers, it
is fine for it to be defined to a configure-time check from the build
system.

Warning: Although Waf and Windows makefiles are updated they are not
         tested an will probably required tuning.

The flags in this variables are used to tune the linker behavior on the
final libgeany (currently set the version information), so should only
used on really linked libraries, not Libtool helper libraries.

They are connected inside the library now rather than using GModule to
find the symbols. Mark local callback handlers as static since they
aren't global or exported anymore, they should be static. Since they're
static now, all of the forward-declarations of the functions local to
callbacks.c are pointless, so just remove them.

This prevents having to export those callbacks and put them in the
global namespace. Also, use inline shell script in Makefile.am instead
of a Python script which should be more portable (by default) and gets
rid of the helper script.

Checks if the compiler supports -fvisibility and the linker supports
-dynamic-list arguments and use them instead of hardcoding. The new
geany-lib.m4 also accomodates future use of Libtool versioning.

This will allow plugins to link against the core when accessing API
functions, now that the macro/struct/funcptr stuff is gone.

Also convert the helper libraries into Libtool helper libraries as
linking a shared library against static libraries is (apparently) not
portable.

Add rest of headers needed for declarations of all public API
functions. Add HAVE_PLUGINS define to geanyplugins.h since some headers
need this and it should always be valid for this header.
geanyfunctions.h left for source-level backwards compatibility for
plugins which might `#include` this header directly. I don't know why
they do it, but some Geany-Plugins do this.

It only needs to be specified in one place for each function.

This allows them to be dynamically exported when -fvisibility=hidden
is applied.

TODO: remove the CFLAGS hack in configure.ac

Adds a new header `pluginexport.h` to put the macros in, could be
moved into an existing header (support.h?) by I didn't want to drag
a bunch of existing stuff into the source files for this one macro.

TagManager has relative include, this could be fixed by changing the
include directories for it if it's a problem. Mark the Scintilla
functions exported by re-declaring them in sciwrappers.c with the
attribute to avoid changing upstream Scintilla code.

Uses a Python script to generate a listing used by the linker to
determine which symbols to dynamically export. This provides finer
grained control of which symbols are dynamically exported, limiting
only to the ones needed for GtkBuilder signal connections.

The build system integration could probably be done a little cleaner.

Enable new Scintlla lexer.cpp.verbatim.strings.allow.escapes lexer
property for ObjectiveC.

Also remove extra padding around the button's image to reduce its size
and try and avoid it expanding the tab's height.

This at least fixes the editor tabs height on Adwaita theme, where they
were 1px taller than normal.

Use the short name for EOL mode in the statusbar