[PATCH] IntelFsp2Pkg: 41d739e breaks flat tree build

[Star Zeng <star.zeng@intel.com>]

There may be no environment variable PACKAGES_PATH defined
in flat tree, then 41d739e breaks flat tree build.
This patch is to update GenCfgOpt.py to be compatible with
both flat tree and package path build.

Cc: Richard Thomaiyar <richard.marian.thomaiyar@intel.com>
Cc: Maurice Ma <maurice.ma@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Giri P Mudusuru <giri.p.mudusuru@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
---
 IntelFsp2Pkg/Tools/GenCfgOpt.py | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/IntelFsp2Pkg/Tools/GenCfgOpt.py b/IntelFsp2Pkg/Tools/GenCfgOpt.py
index 0675b55c169c..7658b7fc5cb0 100644
--- a/IntelFsp2Pkg/Tools/GenCfgOpt.py
+++ b/IntelFsp2Pkg/Tools/GenCfgOpt.py
@@ -524,11 +524,14 @@ EndList
                                         IncludeFilePath = Match.group(1)
                                         IncludeFilePath = self.ExpandMacros(IncludeFilePath)
                                         PackagesPath = os.getenv("PACKAGES_PATH")
-                                        for PackagePath in PackagesPath.split(os.pathsep):
-                                            IncludeFilePathAbs = os.path.join(os.path.normpath(PackagePath), os.path.normpath(IncludeFilePath))
-                                            if os.path.exists(IncludeFilePathAbs):
-                                                IncludeDsc  = open(IncludeFilePathAbs, "r")
-                                                break
+                                        if PackagesPath:
+                                          for PackagePath in PackagesPath.split(os.pathsep):
+                                              IncludeFilePathAbs = os.path.join(os.path.normpath(PackagePath), os.path.normpath(IncludeFilePath))
+                                              if os.path.exists(IncludeFilePathAbs):
+                                                  IncludeDsc  = open(IncludeFilePathAbs, "r")
+                                                  break
+                                        else:
+                                          IncludeDsc  = open(IncludeFilePath, "r")
                                         if IncludeDsc == None:
                                             print("ERROR: Cannot open file '%s'" % IncludeFilePath)
                                             raise SystemExit
-- 
2.7.0.windows.1