moz seem to have no idea what their own damn build system is doing...

--- thunderbird-52.6.0/extensions/spellcheck/hunspell/glue/moz.build	2018-01-24 03:06:15.000000000 +0000
+++ thunderbird-52.6.0/extensions/spellcheck/hunspell/glue/moz.build	2018-03-12 09:17:05.386773708 +0000
@@ -16,6 +16,9 @@
 if CONFIG['MOZ_SYSTEM_HUNSPELL']:
     CXXFLAGS += CONFIG['MOZ_HUNSPELL_CFLAGS']
 else:
+    # This variable is referenced in configure.in.  Make sure to change that file
+    # too if you need to change this variable.
+    DEFINES['HUNSPELL_STATIC'] = True
     LOCAL_INCLUDES += ['../src']
 
 LOCAL_INCLUDES += [
@@ -33,7 +36,3 @@
      'RemoteSpellCheckEngineChild.h',
      'RemoteSpellCheckEngineParent.h',
 ]
-
-# This variable is referenced in configure.in.  Make sure to change that file
-# too if you need to change this variable.
-DEFINES['HUNSPELL_STATIC'] = True