[pango] build: Make harfbuzz a required dependency

[Matthias Clasen <matthiasc src gnome org>]

commit f474d224efdc72042e947490303efafe0f14c041
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jul 24 20:33:50 2019 -0400

    build: Make harfbuzz a required dependency
    
    We can't do without anymore, so report a clear
    error if harfbuzz is not found.

 meson.build | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index 72198036..8c41381c 100644
--- a/meson.build
+++ b/meson.build
@@ -256,10 +256,12 @@ if not harfbuzz_dep.found()
                             fallback: ['harfbuzz', 'libharfbuzz_dep'])
 endif
 
-if harfbuzz_dep.found()
-  pango_deps += harfbuzz_dep
+if not harfbuzz_dep.found()
+  error('harfbuzz not found')
 endif
 
+pango_deps += harfbuzz_dep
+
 # Only use FontConfig fallback when required or requested
 fontconfig_required = (host_system != 'windows' and host_system != 'darwin') or get_option('use_fontconfig')