Bug 916257 - part 3 - write ALL_IPDLSRCS and CPPSRCS in one go; r=gps

python/mozbuild/mozbuild/backend/recursivemake.py

@@ -5,6 +5,7 @@
 from __future__ import unicode_literals
 
 import errno
+import itertools
 import logging
 import os
 import types
@@ -289,8 +290,9 @@ class RecursiveMakeBackend(CommonBackend):
             'ipc', 'ipdl', 'ipdlsrcs.mk'))
         mk = mozmakeutil.Makefile()
 
-        for p in sorted(self._ipdl_sources):
+        sorted_ipdl_sources = list(sorted(self._ipdl_sources))
-            mk.add_statement('ALL_IPDLSRCS += %s\n' % p)
+        mk.add_statement('ALL_IPDLSRCS := %s\n' % ' '.join(sorted_ipdl_sources))
+
         def files_from(ipdl):
             base = os.path.basename(ipdl)
             root, ext = os.path.splitext(base)
@@ -303,7 +305,8 @@ class RecursiveMakeBackend(CommonBackend):
                               '%sParent.cpp' % root])
             return files
 
-            mk.add_statement('CPPSRCS += %s\n' % ' '.join(files_from(p)))
+        ipdl_cppsrcs = itertools.chain(*[files_from(p) for p in sorted_ipdl_sources])
+        mk.add_statement('CPPSRCS := %s\n' % ' '.join(ipdl_cppsrcs))
 
         mk.add_statement('IPDLDIRS := %s\n' % ' '.join(sorted(set(os.path.dirname(p)
             for p in self._ipdl_sources))))