Bug 1578825 - add a strict version check for the NDK version; r=nalexander

One less thing for configurations to vary is a good thing.  This change
also means that when we do NDK bumps that introduce some kind of weird
incompatible change, configuration with a newly-pulled tree and an old
NDK halts at configure, rather than giving weird build errors.

Differential Revision: https://phabricator.services.mozilla.com/D44705

--HG--
extra : moz-landing-system : lando

build/moz.configure/android-ndk.configure

@@ -81,6 +81,7 @@ add_old_configure_assignment('android_ndk', ndk)
 @depends(ndk)
 @checking('for android ndk version')
 @imports(_from='__builtin__', _import='open')
+@imports(_from='mozboot.android', _import='NDK_VERSION')
 def ndk_version(ndk):
     if not ndk:
         # Building 'js/src' for non-Android.
@@ -100,6 +101,20 @@ def ndk_version(ndk):
         if not major or not minor:
             die('Unexpected NDK version string: ' + version)
 
+        # source.properties contains a $MAJOR.$MINOR.$PATCH revision number,
+        # but the more common nomenclature that Google uses is alphanumeric
+        # version strings like "r20" or "r19c".  Convert the source.properties
+        # notation into an alphanumeric string.
+        int_minor = int(minor)
+        alphas = "abcdefghijklmnop"
+        ascii_minor = alphas[int_minor] if int_minor > 0 else ''
+        human = "r%s%s" % (major, ascii_minor)
+
+        if NDK_VERSION != human:
+            die('The only supported version of the NDK is %s (have %s)\n'
+                'Please run |mach bootstrap| '
+                'to install the correct NDK.' % (NDK_VERSION, human))
+
         return namespace(
             major=major,
             minor=minor,