--- a/build/moz.configure/init.configure
+++ b/build/moz.configure/init.configure
@@ -391,16 +391,19 @@ def split_triplet(triplet):
         canonical_cpu = 'mips32'
         endianness = 'little' if 'el' in cpu else 'big'
     elif cpu in ('mips64', 'mips64el'):
         canonical_cpu = 'mips64'
         endianness = 'little' if 'el' in cpu else 'big'
     elif cpu.startswith('aarch64'):
         canonical_cpu = 'aarch64'
         endianness = 'little'
+    elif cpu in ('m68k'):
+        canonical_cpu = 'm68k'
+        endianness = 'big'
     else:
         die('Unknown CPU type: %s' % cpu)
 
     return namespace(
         alias=triplet,
         cpu=CPU(canonical_cpu),
         bitness=CPU_bitness[canonical_cpu],
         kernel=Kernel(canonical_kernel),

--- a/python/mozbuild/mozbuild/configure/constants.py
+++ b/python/mozbuild/mozbuild/configure/constants.py
@@ -39,16 +39,17 @@ Kernel = EnumString.subclass(
 )
 
 CPU_bitness = {
     'aarch64': 64,
     'Alpha': 32,
     'arm': 32,
     'hppa': 32,
     'ia64': 64,
+    'm68k': 32,
     'mips32': 32,
     'mips64': 64,
     'ppc': 32,
     'ppc64': 64,
     's390': 32,
     's390x': 64,
     'sparc': 32,
     'sparc64': 64,
@@ -80,16 +81,17 @@ CPU_preprocessor_checks = OrderedDict((
     ('ppc64', '__powerpc64__'),
     ('ppc', '__powerpc__'),
     ('Alpha', '__alpha__'),
     ('hppa', '__hppa__'),
     ('sparc64', '__sparc__ && __arch64__'),
     ('sparc', '__sparc__'),
     ('mips64', '__mips64'),
     ('mips32', '__mips__'),
+    ('m68k', '__m68k__'),
 ))
 
 assert sorted(CPU_preprocessor_checks.keys()) == sorted(CPU.POSSIBLE_VALUES)
 
 kernel_preprocessor_checks = {
     'Darwin': '__APPLE__',
     'DragonFly': '__DragonFly__',
     'FreeBSD': '__FreeBSD__',

--- a/python/mozbuild/mozbuild/test/configure/test_toolchain_configure.py
+++ b/python/mozbuild/mozbuild/test/configure/test_toolchain_configure.py
@@ -1032,16 +1032,19 @@ class LinuxCrossCompileToolchainTest(Bas
         },
         'mips64-unknown-linux-gnuabi64': big_endian + {
             '__mips64': 1,
             '__mips__': 1,
         },
         'mips-unknown-linux-gnu': big_endian + {
             '__mips__': 1,
         },
+        'm68k-unknown-linux-gnu': big_endian + {
+            '__m68k__': 1,
+        },
     }
 
     PLATFORMS['powerpc64le-unknown-linux-gnu'] = \
         PLATFORMS['powerpc64-unknown-linux-gnu'] + GCC_PLATFORM_LITTLE_ENDIAN
     PLATFORMS['mips64el-unknown-linux-gnuabi64'] = \
         PLATFORMS['mips64-unknown-linux-gnuabi64'] + GCC_PLATFORM_LITTLE_ENDIAN
     PLATFORMS['mipsel-unknown-linux-gnu'] = \
         PLATFORMS['mips-unknown-linux-gnu'] + GCC_PLATFORM_LITTLE_ENDIAN