Switch build system to mesonbuild.

There is no more integrated build of dependencies in the build system.
Dependencies are discovered using pkg-config except for ctpp2 where there
is no pkg-config file.

meson.build

@@ -0,0 +1,61 @@
+project('kiwixlib', 'cpp',
+  version : '1.0.0',
+  license : 'GPL')
+
+compiler = meson.get_compiler('cpp')
+
+thread_dep = dependency('threads')
+zlib_dep = dependency('zlib')
+bzip_dep = dependency('bzip2')
+libicu_dep = dependency('icu-i18n')
+lzma_dep = dependency('liblzma')
+libzim_dep = dependency('zimlib')
+pugixml_dep = dependency('pugixml')
+aria2_dep = find_program('aria2c')
+
+ctpp2_prefix_install = get_option('ctpp2-install-prefix')
+if get_option('default_library') == 'static'
+    libname = 'ctpp2-st'
+else
+    libname = 'ctpp2'
+endif
+if ctpp2_prefix_install == ''
+  if not compiler.has_header('ctpp2/CTPP2Logger.hpp')
+    error('ctpp2/CTPP2Logger.hppnot found')
+  endif
+  ctpp2_lib = compiler.find_library(libname)
+  ctpp2_dep = declare_dependency(dependencies:[ctpp2_lib])
+else
+  ctpp2_include_path = ctpp2_prefix_install + '/include'
+  ctpp2_include_args = ['-I'+ctpp2_include_path]
+  if not compiler.has_header('ctpp2/CTPP2Logger.hpp', args:ctpp2_include_args)
+    error('ctpp2/CTPP2Logger.hppnot found')
+  endif
+  ctpp2_include_path = include_directories(ctpp2_include_path, is_system:true)
+  ctpp2_lib_path = ctpp2_prefix_install+'/lib'
+  ctpp2_lib = compiler.find_library(libname, dirs:ctpp2_lib_path)
+  ctpp2_dep = declare_dependency(include_directories:ctpp2_include_path, dependencies:[ctpp2_lib])
+endif
+
+xapian_dep = dependency('xapian-core', required:false)
+if xapian_dep.found()
+    message('xapian_dep found')
+else
+    message('xapian_dep not found')
+endif
+
+all_deps = [thread_dep, zlib_dep, libicu_dep, lzma_dep, libzim_dep, ctpp2_dep, xapian_dep, pugixml_dep, bzip_dep]
+
+inc = include_directories('include')
+
+subdir('include')
+subdir('src')
+
+pkg_mod = import('pkgconfig')
+pkg_mod.generate(libraries : kiwixlib,
+                 version : '1.0',
+                 name : 'libkiwix',
+                 filebase : 'kiwix',
+                 description : 'A library that contains a lot of things used by used by other kiwix programs',
+                 requires: ['zimlib', 'zlib', 'xapian-core', 'icu-i18n', 'liblzma', 'bzip2', 'pugixml'])
+