diff -ur mozjs-60.1.0/build/moz.configure/init.configure mozjs-60.1.0-x32/build/moz.configure/init.configure
--- mozjs-60.1.0/build/moz.configure/init.configure	2018-06-19 00:23:55.000000000 +0200
+++ mozjs-60.1.0-x32/build/moz.configure/init.configure	2019-03-31 10:40:40.743730317 +0200
@@ -630,6 +630,8 @@
         endianness = 'little'
     elif cpu in ('x86_64', 'ia64'):
         canonical_cpu = cpu
+        if os.endswith('gnux32'):
+            canonical_cpu = 'x32'
         endianness = 'little'
     elif cpu in ('s390', 's390x'):
         canonical_cpu = cpu
--- firefox-60.7.0/mfbt/RandomNum.cpp.orig	2019-05-24 22:04:38.196451155 +0200
+++ firefox-60.7.0/mfbt/RandomNum.cpp	2019-05-24 22:10:43.717804289 +0200
@@ -58,7 +58,9 @@
 
 // Older glibc versions don't define SYS_getrandom, so we define it here if
 // it's not available. See bug 995069.
-#  if defined(__x86_64__)
+#  if defined(__x86_64__) && defined(__ILP32__)
+#    define GETRANDOM_NR (__X32_SYSCALL_BIT + 318)
+#  elif defined(__x86_64__)
 #    define GETRANDOM_NR 318
 #  elif defined(__i386__)
 #    define GETRANDOM_NR 355
diff -ur mozjs-60.1.0/python/mozbuild/mozbuild/configure/constants.py mozjs-60.1.0-x32/python/mozbuild/mozbuild/configure/constants.py
--- mozjs-60.1.0/python/mozbuild/mozbuild/configure/constants.py	2018-06-19 00:24:03.000000000 +0200
+++ mozjs-60.1.0-x32/python/mozbuild/mozbuild/configure/constants.py	2019-03-31 10:39:21.792681467 +0200
@@ -57,6 +57,7 @@
     'sparc64': 64,
     'x86': 32,
     'x86_64': 64,
+    'x32': 32,
 }
 
 CPU = EnumString.subclass(*CPU_bitness.keys())
@@ -73,6 +74,7 @@
 
 # The order of those checks matter
 CPU_preprocessor_checks = OrderedDict((
+    ('x32', '__x86_64__ && __ILP32__'),
     ('x86', '__i386__ || _M_IX86'),
     ('x86_64', '__x86_64__ || _M_X64'),
     ('arm', '__arm__ || _M_ARM'),