scons: Use env and not main in SConscripts.

"env" is the environment for the current variant, where "main" is the
environment that was derived from.

Change-Id: I71e30684aa82a297241820502f204400c89c80cf
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56890
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>

src/base/stats/SConscript

@@ -35,7 +35,7 @@ Source('storage.cc')
 Source('text.cc')
 
 if env['HAVE_HDF5']:
-    if main['GCC']:
+    if env['GCC']:
         Source('hdf5.cc', append={'CXXFLAGS': '-Wno-deprecated-copy'})
     else:
         Source('hdf5.cc')

src/systemc/core/SConscript

@@ -65,7 +65,7 @@ if env['USE_SYSTEMC']:
         Source('python.cc')
         Source('sc_main_python.cc')
         append = {}
-        with gem5_scons.Configure(main) as conf:
+        with gem5_scons.Configure(env) as conf:
             for flag in ('-Wno-self-assign-overloaded', '-Wno-self-assign'):
                 if conf.CheckCxxFlag(flag, autoadd=False):
                     append['CCFLAGS'] = [flag]
@@ -73,7 +73,7 @@ if env['USE_SYSTEMC']:
         Source('sc_time_python.cc', append=append)
 
     # Disable the false positive warning for the event members of the scheduler.
-    with gem5_scons.Configure(main) as conf:
+    with gem5_scons.Configure(env) as conf:
         flag = '-Wno-free-nonheap-object'
         append = {}
         if conf.CheckCxxFlag(flag, autoadd=False):

src/systemc/dt/int/SConscript

@@ -28,7 +28,7 @@ Import('*')
 from gem5_scons.util import compareVersions
 
 if env['USE_SYSTEMC']:
-    if main['GCC'] and compareVersions(main['CXXVERSION'], '10.0') >= 0:
+    if env['GCC'] and compareVersions(env['CXXVERSION'], '10.0') >= 0:
         disable_false_positives = {
             "CCFLAGS": [ "-Wno-array-bounds",
                          "-Wno-stringop-overflow" ]