pidgin/pidgin

Fix installed Pidgin headers

2021-05-16, Elliott Sales de Andrade
8f377fd478c0
Fix installed Pidgin headers

* Install Pidgin headers to the correct directory.
The main header includes subheaders as `pidgin/...`, so they need to be installed that way.
* Add libhandy to pidgin pkgconfig.
* Ensure `pidginenums.h` is installed.
* Add some variables around pidgin include install paths.

Testing Done:
Compiled a file with `#include ` using `pkgconf --cflags pidgin-3`.

Reviewed at https://reviews.imfreedom.org/r/656/
#include <winver.h>
VS_VERSION_INFO VERSIONINFO
FILEVERSION @PURPLE_MAJOR_VERSION@,@PURPLE_MINOR_VERSION@,@PURPLE_MICRO_VERSION@,0
PRODUCTVERSION @PURPLE_MAJOR_VERSION@,@PURPLE_MINOR_VERSION@,@PURPLE_MICRO_VERSION@,0
FILEFLAGSMASK 0
FILEFLAGS 0
FILEOS VOS__WINDOWS32
FILETYPE VFT_APP
FILESUBTYPE VFT2_UNKNOWN
BEGIN
BLOCK "StringFileInfo"
BEGIN
BLOCK "040904B0"
BEGIN
VALUE "CompanyName", "The Pidgin developer community"
VALUE "FileDescription", "Finch UI library"
VALUE "FileVersion", "@PURPLE_VERSION@"
VALUE "InternalName", "libfinch"
VALUE "LegalCopyright", "Copyright (C) 1998-2014 The Pidgin developer community (See the COPYRIGHT file in the source distribution)."
VALUE "OriginalFilename", "libfinch-@PURPLE_API_VERSION@.dll"
VALUE "ProductName", "Finch"
VALUE "ProductVersion", "@PURPLE_VERSION@"
END
END
BLOCK "VarFileInfo"
BEGIN
VALUE "Translation", 0x409, 1200
END
END