meson: we can now build libmain!

Change-Id: I2333a18d790df843d07163ff884c80095d89e0cc

meson.build

@@ -197,3 +197,5 @@ subdir('src/libstore')
 subdir('src/libfetchers')
 # libexpr depends on libfetchers.
 subdir('src/libexpr')
+# libmain depends on libutil and libstore.
+subdir('src/libmain')

src/libexpr/meson.build

@@ -82,3 +82,8 @@ libexpr = library(
     boost,
   ],
 )
+
+liblixexpr = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libexpr,
+)

src/libmain/meson.build

@@ -0,0 +1,16 @@
+libmain_sources = files(
+  'common-args.cc',
+  'loggers.cc',
+  'progress-bar.cc',
+  'shared.cc',
+  'stack.cc',
+)
+
+libmain = library(
+  'main',
+  libmain_sources,
+  dependencies : [
+    liblixutil,
+    liblixstore,
+  ],
+)