--- a/build/unix/elfhack/inject/moz.build
+++ b/build/unix/elfhack/inject/moz.build
@@ -12,13 +12,11 @@ elif CONFIG['TARGET_CPU'].startswith('ar
     cpu = 'arm'
 else:
     cpu = CONFIG['TARGET_CPU']
 
 GENERATED_SOURCES += [
     "%s.c" % cpu,
 ]
 
-DEFINES['ELFHACK_BUILD'] = True
-
 NO_PGO = True
 
 NO_VISIBILITY_FLAGS = True

--- a/build/unix/elfhack/moz.build
+++ b/build/unix/elfhack/moz.build
@@ -20,11 +20,9 @@ if not CONFIG['CROSS_COMPILE']:
 
 HOST_SOURCES += [
     'elf.cpp',
     'elfhack.cpp',
 ]
 
 HostProgram('elfhack')
 
-DEFINES['ELFHACK_BUILD'] = True
-
 NO_PGO = True

--- a/mozilla-config.h.in
+++ b/mozilla-config.h.in
@@ -36,21 +36,18 @@
 #pragma clang diagnostic pop
 #endif
 
 /*
  * Force-include Char16.h in order to define PRUnichar as char16_t everywhere.
  * Note that this should be the first #include to make sure that prtypes.h does
  * not attempt to define PRUnichar.  This includes the following hunspell-specific
  * includes.
- *
- * We don't use this to build elfhack and elf-dynstr-gc since those builds happen
- * during the export tier.  Also, disable this when building assembly files too.
  */
-#if !defined(ELFHACK_BUILD) && !defined(__ASSEMBLER__)
+#if !defined(__ASSEMBLER__)
 #include "mozilla/Char16.h"
 #endif
 
 /*
  * Force-include hunspell_alloc_hooks.h and hunspell_fopen_hooks.h for hunspell,
  * so that we don't need to modify them directly.
  *
  * HUNSPELL_STATIC is defined in extensions/spellcheck/hunspell/src/Makefile.in,