buildman: Support disabling LTO

This cuts down build performance considerably and is not always needed,
when checking for build errors, etc.

Add a flag to disable it.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/buildman/builder.py

@@ -194,6 +194,7 @@ class Builder:
         work_in_output: Use the output directory as the work directory and
             don't write to a separate output directory.
         thread_exceptions: List of exceptions raised by thread jobs
+        no_lto (bool): True to set the NO_LTO flag when building
 
     Private members:
         _base_board_dict: Last-summarised Dict of boards
@@ -253,7 +254,7 @@ class Builder:
                  config_only=False, squash_config_y=False,
                  warnings_as_errors=False, work_in_output=False,
                  test_thread_exceptions=False, adjust_cfg=None,
-                 allow_missing=False):
+                 allow_missing=False, no_lto=False):
         """Create a new Builder object
 
         Args:
@@ -292,6 +293,7 @@ class Builder:
                     C=val to set the value of C (val must have quotes if C is
                         a string Kconfig
             allow_missing: Run build with BINMAN_ALLOW_MISSING=1
+            no_lto (bool): True to set the NO_LTO flag when building
 
         """
         self.toolchains = toolchains
@@ -331,6 +333,7 @@ class Builder:
         self.adjust_cfg = adjust_cfg
         self.allow_missing = allow_missing
         self._ide = False
+        self.no_lto = no_lto
 
         if not self.squash_config_y:
             self.config_filenames += EXTRA_CONFIG_FILENAMES