[gexiv2] meson.build: improve handling of vapi

[Jens Georg <jensgeorg src gnome org>]

commit 5d69244e04c2e9e5ab414611c415526a68369526
Author: Marty E. Plummer <hanetzer startmail com>
Date:   Sun Jan 13 13:33:32 2019 -0600

    meson.build: improve handling of vapi
    
    As it currently stands the vapi files are not generatable on linux
    distros which do not provide unversioned valac/vapigen. Use instead
    meson's add_languages function to handle detection of existing vala
    toolchain, which will check the VALAC and VAPIGEN env vars.
    
    Signed-off-by: Marty E. Plummer <hanetzer startmail com>

 meson.build      |  4 +---
 test/meson.build | 14 +++++---------
 2 files changed, 6 insertions(+), 12 deletions(-)
---
diff --git a/meson.build b/meson.build
index b0f9045..209b3e9 100644
--- a/meson.build
+++ b/meson.build
@@ -15,11 +15,9 @@ gobject = dependency('gobject-2.0', version : '>= 2.38.0')
 gio = dependency('gio-2.0', version : '>= 2.32.0')
 
 gir = find_program('g-ir-scanner', required: false)
-vapigen = find_program('vapigen', required: false)
-vala = find_program('valac', required: false)
 
 introspection_available = gir.found() and get_option('introspection')
-vapi_available = introspection_available and vapigen.found() and get_option('vapi')
+vapi_available = introspection_available and add_languages('vala', required: get_option('vapi')) and 
get_option('vapi')
 
 subdir('gexiv2')
 
diff --git a/test/meson.build b/test/meson.build
index a50f9df..9e99477 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -17,15 +17,11 @@ regression_test = executable('gexiv2-regression', 'gexiv2-regression.c',
 test('regression', regression_test, env : test_env)
 
 if vapi_available
-  valac = find_program('valac')
-  if valac.found()
-    add_languages('vala')
-    executable('gexiv2-dump',
-               'gexiv2-dump.vala',
-               include_directories : include_directories('..'),
-               dependencies : [gobject, vapi, gio],
-               link_with : gexiv2)
-  endif
+  executable('gexiv2-dump',
+             'gexiv2-dump.vala',
+             include_directories : include_directories('..'),
+             dependencies : [gobject, vapi, gio],
+             link_with : gexiv2)
 endif
 
 if python2_available