SConstruct: Add comments on scons 3.0.5 breakage.

Changes to env between Configure() and Finish() get lost.

1 files changed, 8 insertions, 0 deletions

diff --git a/SConstruct b/SConstruct
index b354feda..0af984ed 100644
--- a/SConstruct
+++ b/SConstruct
@@ -658,6 +658,8 @@ def GetLoadPath(context):
 cleaning = env.GetOption('clean')
 helping = env.GetOption('help')
 
+# from scons 3.0.5, any changes to env after this, until after
+# config.Finish(), will be lost.
 config = Configure(env, custom_tests={
     'CheckPKG': CheckPKG,
     'CheckXsltproc': CheckXsltproc,
@@ -667,6 +669,7 @@ config = Configure(env, custom_tests={
     'CheckHeaderDefines': CheckHeaderDefines,
     'GetPythonValue': GetPythonValue})
 
+# this gets lost on scons 3.0.5
 # Always set up LIBPATH so that cleaning works properly.
 env.Prepend(LIBPATH=[os.path.realpath(os.curdir)])
 
@@ -686,6 +689,7 @@ else:
     # clang accepts -pthread, then warns it is unused.
     if ((config.CheckCompilerOption("-pthread") and
          not sys.platform.startswith('darwin'))):
+        # this gets lost on scons 3.0.5
         env.MergeFlags("-pthread")
 
     confdefs = ["/* gpsd_config.h generated by scons, do not hand-hack. */\n"]
@@ -773,6 +777,7 @@ else:
     if env['dbus_export'] and config.CheckPKG('dbus-1'):
         confdefs.append("#define HAVE_DBUS 1\n")
         dbusflags = pkg_config("dbus-1")
+        # this gets lost on scons 3.0.5
         env.MergeFlags(dbusflags)
     else:
         confdefs.append("/* #undef HAVE_DBUS */\n")
@@ -887,6 +892,7 @@ else:
             confdefs.append("/* #undef HAVE_%s */\n" % f.upper())
 
     if config.CheckHeader(["sys/types.h", "sys/time.h", "sys/timepps.h"]):
+        # this gets lost on scons 3.0.5
         env.MergeFlags("-DHAVE_SYS_TIMEPPS_H=1")
         kpps = True
     else:
@@ -970,6 +976,7 @@ else:
         announce("Build of man and HTML documentation is disabled.")
     if manbuilder:
         # 18.2. Attaching a Builder to a Construction Environment
+        # this gets lost on scons 3.0.5
         env.Append(BUILDERS = {"Man" : Builder(action=manbuilder,
                                                src_suffix=".xml")})
         env.Append(BUILDERS = {"HTML" : Builder(action=htmlbuilder,
@@ -1097,6 +1104,7 @@ if env['python']:  # May have been turned off by error
 
 
 env = config.Finish()
+# env can now be modified.
 
 if not (cleaning or helping):