Support giving the header path in KCONFIG_AUTOHEADER

This environment variable is used by the C tools. Use it when
filename=None is passed to write_autoconf(), and default to
include/generated/autoconf.h for compatibility.

Also update genconfig.py to use KCONFIG_AUTOHEADER if set when no
--header-path is passed. If KCONFIG_AUTOHEADER isn't set, keep
defaulting to 'config.h' for backwards compatibility. It's probably a
saner default for tools as well.

1 files changed, 16 insertions, 5 deletions

diff --git a/genconfig.py b/genconfig.py
index 96124c5..b202a5b 100755
--- a/genconfig.py
+++ b/genconfig.py
@@ -35,7 +35,6 @@ import sys
 import kconfiglib
 
 
-DEFAULT_HEADER_PATH = "config.h"
 DEFAULT_SYNC_DEPS_PATH = "deps/"
 
 
@@ -47,9 +46,11 @@ def main():
     parser.add_argument(
         "--header-path",
         metavar="HEADER_FILE",
-        default=DEFAULT_HEADER_PATH,
-        help="Path for the generated header file (default: {})"
-             .format(DEFAULT_HEADER_PATH))
+        help="""
+Path to write the generated header file to. If not specified, the path in the
+environment variable KCONFIG_AUTOHEADER is used if it is set, and 'config.h'
+otherwise.
+""")
 
     parser.add_argument(
         "--config-out",
@@ -107,7 +108,17 @@ only supported for backwards compatibility).
     kconf = kconfiglib.Kconfig(args.kconfig_filename)
     kconf.load_config()
 
-    kconf.write_autoconf(args.header_path)
+    if args.header_path is None:
+        if "KCONFIG_AUTOHEADER" in os.environ:
+            kconf.write_autoconf()
+        else:
+            # Kconfiglib defaults to include/generated/autoconf.h to be
+            # compatible with the C tools. 'config.h' is used here instead for
+            # backwards compatibility. It's probably a saner default for tools
+            # as well.
+            kconf.write_autoconf("config.h")
+    else:
+        kconf.write_autoconf(args.header_path)
 
     if args.config_out is not None:
         kconf.write_config(args.config_out, save_old=False)