Bug 1257051 - Use separate target triplets for iOS and OSX. r=ted

This aligns with the triplets used by clang/llvm. Technically, this
won't break iOS builds still using -darwin triplets until we move
MOZ_IOS_SDK to moz.configure and actively reject non iOS targets with
the iOS sdk.

Also allow to distinguish iOS and OSX with target.os.

build/moz.configure/init.configure

@@ -360,7 +360,11 @@ def split_triplet(triplet):
     elif os.startswith('mingw'):
         canonical_os = canonical_kernel = 'WINNT'
     elif os.startswith('darwin'):
-        canonical_os = canonical_kernel = 'Darwin'
+        canonical_kernel = 'Darwin'
+        canonical_os = 'OSX'
+    elif os.startswith('ios'):
+        canonical_kernel = 'Darwin'
+        canonical_os = 'iOS'
     elif os.startswith('dragonfly'):
         canonical_os = canonical_kernel = 'DragonFly'
     elif os.startswith('freebsd'):
@@ -434,7 +438,13 @@ def target(value, host):
 def host_and_target_for_old_configure(host, target):
     # Autoconf needs these set
     add_old_configure_arg('--host=%s' % host.alias)
-    add_old_configure_arg('--target=%s' % target.alias)
+
+    target_alias = target.alias
+    # old-configure does plenty of tests against $target and $target_os
+    # and expects darwin for iOS, so make it happy.
+    if target.os == 'iOS':
+        target_alias = target_alias.replace('-ios', '-darwin')
+    add_old_configure_arg('--target=%s' % target_alias)
 
 
 # These variables are for compatibility with the current moz.builds and
@@ -444,7 +454,8 @@ def target_variables(target):
     if target.kernel == 'kFreeBSD':
         os_target = 'GNU/kFreeBSD'
         os_arch = 'GNU_kFreeBSD'
-    elif target.kernel == 'Linux' and target.os == 'GNU':
+    elif target.kernel == 'Darwin' or (target.kernel == 'Linux' and
+                                       target.os == 'GNU'):
         os_target = target.kernel
         os_arch = target.kernel
     else:

moz.configure

@@ -121,7 +121,7 @@ check_prog('ZIP', ('zip',))
 
 @depends(target)
 def mac_programs(target):
-    if target.os == 'Darwin':
+    if target.kernel == 'Darwin':
         check_prog('DSYMUTIL', ('dsymutil', 'llvm-dsymutil'), allow_missing=True)
         check_prog('GENISOIMAGE', ('genisoimage',), allow_missing=True)