Port build to meson

[Cogitri]

Meson is a next generation buildsystem with many advantages:

• Way faster configuration times
• Clearer error messages
• Easier to write
• Less errorprone

If you like this for qalculate-gtk I wouldn't mind doing the same port for libqalculate.

A few notes:

The build with GCC10 seems to fail currently, compiling with clang 10 works just fine though so I'm not sure if this is caused by this change. The error is:

FAILED: src/qalculate-gtk.p/interface.cc.o 
c++ -Isrc/qalculate-gtk.p -Isrc -I../src -I. -I.. -Idata -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/gtk-3.0 -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/fribidi -I/usr/include/libxml2 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/gio-unix-2.0 -I/usr/include/atk-1.0 -I/usr/include/at-spi2-atk/2.0 -I/usr/include/dbus-1.0 -I/usr/lib64/dbus-1.0/include -I/usr/include/at-spi-2.0 -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wnon-virtual-dtor -Wextra -std=c++11 -g -DHAVE_CONFIG_H=1 -pthread -MD -MQ src/qalculate-gtk.p/interface.cc.o -MF src/qalculate-gtk.p/interface.cc.o.d -o src/qalculate-gtk.p/interface.cc.o -c ../src/interface.cc
In file included from /usr/include/c++/10/ext/hash_map:60,
                 from ../src/interface.cc:49:
/usr/include/c++/10/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header which may be removed without further notice at a future date. Please use a non-deprecated interface with equivalent functionality instead. For a listing of replacement headers and interfaces, consult the file backward_warning.h. To disable this warning use -Wno-deprecated. [-Wcpp]
   32 | #warning \
      |  ^~~~~~~
In file included from /usr/include/c++/10/ext/hash_map:64,
                 from ../src/interface.cc:49:
/usr/include/c++/10/backward/hashtable.h: In instantiation of ‘__gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::size_type __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::_M_bkt_num_key(const key_type&, std::size_t) const [with _Val = std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*>; _Key = std::__cxx11::basic_string<char>; _HashFcn = __gnu_cxx::hash<std::__cxx11::basic_string<char> >; _ExtractKey = std::_Select1st<std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*> >; _EqualKey = std::equal_to<std::__cxx11::basic_string<char> >; _Alloc = std::allocator<_GdkPixbuf*>; __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::size_type = long unsigned int; __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::key_type = std::__cxx11::basic_string<char>; std::size_t = long unsigned int]’:
/usr/include/c++/10/backward/hashtable.h:596:30:   required from ‘__gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::size_type __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::_M_bkt_num_key(const key_type&) const [with _Val = std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*>; _Key = std::__cxx11::basic_string<char>; _HashFcn = __gnu_cxx::hash<std::__cxx11::basic_string<char> >; _ExtractKey = std::_Select1st<std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*> >; _EqualKey = std::equal_to<std::__cxx11::basic_string<char> >; _Alloc = std::allocator<_GdkPixbuf*>; __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::size_type = long unsigned int; __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::key_type = std::__cxx11::basic_string<char>]’
/usr/include/c++/10/backward/hashtable.h:519:32:   required from ‘__gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::iterator __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::find(const key_type&) [with _Val = std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*>; _Key = std::__cxx11::basic_string<char>; _HashFcn = __gnu_cxx::hash<std::__cxx11::basic_string<char> >; _ExtractKey = std::_Select1st<std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*> >; _EqualKey = std::equal_to<std::__cxx11::basic_string<char> >; _Alloc = std::allocator<_GdkPixbuf*>; __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::iterator = __gnu_cxx::hashtable<std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*>, std::__cxx11::basic_string<char>, __gnu_cxx::hash<std::__cxx11::basic_string<char> >, std::_Select1st<std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*> >, std::equal_to<std::__cxx11::basic_string<char> >, std::allocator<_GdkPixbuf*> >::iterator; __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::key_type = std::__cxx11::basic_string<char>]’
/usr/include/c++/10/ext/hash_map:213:26:   required from ‘__gnu_cxx::hash_map<_Key, _Tp, _HashFn, _EqualKey, _Alloc>::iterator __gnu_cxx::hash_map<_Key, _Tp, _HashFn, _EqualKey, _Alloc>::find(const key_type&) [with _Key = std::__cxx11::basic_string<char>; _Tp = _GdkPixbuf*; _HashFn = __gnu_cxx::hash<std::__cxx11::basic_string<char> >; _EqualKey = std::equal_to<std::__cxx11::basic_string<char> >; _Alloc = std::allocator<_GdkPixbuf*>; __gnu_cxx::hash_map<_Key, _Tp, _HashFn, _EqualKey, _Alloc>::iterator = __gnu_cxx::hashtable<std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*>, std::__cxx11::basic_string<char>, __gnu_cxx::hash<std::__cxx11::basic_string<char> >, std::_Select1st<std::pair<const std::__cxx11::basic_string<char>, _GdkPixbuf*> >, std::equal_to<std::__cxx11::basic_string<char> >, std::allocator<_GdkPixbuf*> >::iterator; __gnu_cxx::hash_map<_Key, _Tp, _HashFn, _EqualKey, _Alloc>::key_type = std::__cxx11::basic_string<char>]’
../src/interface.cc:1167:3:   required from here
/usr/include/c++/10/backward/hashtable.h:604:23: error: no match for call to ‘(const hasher {aka const __gnu_cxx::hash<std::__cxx11::basic_string<char> >}) (const key_type&)’
  604 |       { return _M_hash(__key) % __n; }
      |                ~~~~~~~^~~~~~~

• The ported build system installs qalculate-search-provider to libexec which is a more fitting dir for this IMHO. We can install it to lib too though, if you prefer that.
• I had to do a few changes to the internationalisation (namely instead of doing intltool-style prefixing with _ meson expects variables to not have special prefixes. That change would break the current Autotools i18n setup, I suppose.

Other than that, meson should produce the same output as autotools does currently, but I can't test this on Windows (it should work just as well or even better though).
I haven't tested ninja -C build dist output yet, I can look into that in a bit.

[hanna-kn]

The build failure is caused by incomplete porting to meson.

AC_CHECK_HEADERS([unordered_map]) defines HAVE_UNORDERED_MAP, and unordered_map will is thereby used instead of deprecated hash_map.

[Cogitri]

Thanks, fixed in the latest version.