[pango/use-hb-fallback-only-when-needed] build: Only use fallback dependency for HarfBuzz when needed

[Chun-wei Fan <fanchunwei src gnome org>]

commit 6408b9830ec8d687b54ba9ad75e20e0547951a13
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Mon Jul 15 11:42:52 2019 +0800

    build: Only use fallback dependency for HarfBuzz when needed
    
    Unfortunately the CMake dependency discovery mechanism is broken in
    Meson, so on MSVC builds we still look first for the HarfBuzz headers
    and .lib's, before we try to use the fallback dependency.
    
    We do, however, want to make use of the fallback if HarfBuzz cannot be
    found since HarfBuzz is now a hard dependency of Pango for all builds.

 meson.build | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index 73b5da2b..c1b737ab 100644
--- a/meson.build
+++ b/meson.build
@@ -232,8 +232,7 @@ harfbuzz_lib=''
 freetype2_lib=''
 fontconfig_lib=''
 
-harfbuzz_dep = dependency('harfbuzz', version: harfbuzz_req_version, required: false,
-                          fallback: ['harfbuzz', 'libharfbuzz_dep'])
+harfbuzz_dep = dependency('harfbuzz', version: harfbuzz_req_version, required: false)
 if harfbuzz_dep.found()
   harfbuzz_pc = 'harfbuzz'
 else
@@ -246,6 +245,14 @@ else
     endif
   endif
 endif
+
+# Remove when Meson acquires ability to declare deps declaratively, or
+# when finding dependencies via CMake files is fixed.
+if not harfbuzz_dep.found()
+harfbuzz_dep = dependency('harfbuzz', version: harfbuzz_req_version,
+                          fallback: ['harfbuzz', 'libharfbuzz_dep'])
+endif
+
 if harfbuzz_dep.found()
   pango_deps += harfbuzz_dep
 endif