Honor $CC/$CC_host and friends in make generator.

pylib/gyp/generator/make.py

Index: pylib/gyp/generator/make.py
diff --git a/pylib/gyp/generator/make.py b/pylib/gyp/generator/make.py
index 2954cae64eb3e223c43c3aa18afb199c177d2934..8332fef4dac13e947619fec9a0f737e2797c9e98 100644
--- a/pylib/gyp/generator/make.py
+++ b/pylib/gyp/generator/make.py
@@ -60,7 +60,6 @@ generator_extra_sources_for_rules = []
 
 def CalculateVariables(default_variables, params):
   """Calculate additional variables for use in the build (called by gyp)."""
-  cc_target = os.environ.get('CC.target', os.environ.get('CC', 'cc'))
   flavor = gyp.common.GetFlavor(params)
   if flavor == 'mac':
     default_variables.setdefault('OS', 'mac')
@@ -255,11 +254,11 @@ all_deps :=
 # This will allow make to invoke N linker processes as specified in -jN.
 LINK ?= %(flock)s $(builddir)/linker.lock $(CXX)
 
-CC.target ?= $(CC)
+CC.target ?= %(CC.target)s
 CFLAGS.target ?= $(CFLAGS)
-CXX.target ?= $(CXX)
+CXX.target ?= %(CXX.target)s
 CXXFLAGS.target ?= $(CXXFLAGS)
-LINK.target ?= $(LINK)
+LINK.target ?= %(LINK.target)s
 LDFLAGS.target ?= $(LDFLAGS)
 AR.target ?= $(AR)
 ARFLAGS.target ?= %(ARFLAGS.target)s
@@ -1891,8 +1890,8 @@ def RunSystemTests(flavor):
   # Compute flags used for building static archives.
   # N.B.: this fallback logic should match the logic in SHARED_HEADER.
   # See comment there for more details.
-  ar_target = os.environ.get('AR.target', os.environ.get('AR', 'ar'))
-  cc_target = os.environ.get('CC.target', os.environ.get('CC', 'cc'))
+  ar_target = GetEnv('AR.target', 'AR_target', 'ar')
+  cc_target = GetEnv('CC.target', 'CC_target', 'cc')
   arflags_target = 'crs'
   # ar -T enables thin archives on Linux. OS X's ar supports a -T flag, but it
   # does something useless (it limits filenames in the archive to 15 chars).
@@ -1915,6 +1914,11 @@ def RunSystemTests(flavor):
            'ARFLAGS.host': arflags_host }
 
 
+def GetEnv(primary, secondary, default):
+  """Look up a key in the environment, falling back to a secondary key
+  and finally falling back to a default value."""
+  return os.environ.get(primary, os.environ.get(secondary, default))
+
 def GenerateOutput(target_list, target_dicts, data, params):
   options = params['options']
   flavor = gyp.common.GetFlavor(params)
@@ -1994,7 +1998,14 @@ def GenerateOutput(target_list, target_dicts, data, params):
     header_params.update({
         'flock': 'lockf',
     })
+
   header_params.update(RunSystemTests(flavor))
+  header_params.update({
+    'CC.target': GetEnv('CC.target', 'CC_target', '$(CC)'),
+    'AR.target': GetEnv('AR.target', 'AR_target', '$(AR)'),
+    'CXX.target': GetEnv('CXX.target', 'CXX_target', '$(CXX)'),
+    'LINK.target': GetEnv('LINK.target', 'LD_target', '$(LINK)'),
+  })
 
   build_file, _, _ = gyp.common.ParseQualifiedTarget(target_list[0])
   make_global_settings_dict = data[build_file].get('make_global_settings', {})