make gyp_skia runnable from any directory

http://codereview.appspot.com/4720042



git-svn-id: http://skia.googlecode.com/svn/trunk@1863 2bbb7eff-a529-9590-31e7-b0007b416f81

Makefile

@@ -52,7 +52,7 @@ clean:
 #
 # For the Mac, we create a convenience symlink to the generated binary.
 %:
-	./gyp_skia
+	$(CWD)/gyp_skia
 ifneq (,$(findstring Linux, $(uname)))
 	$(MAKE) -C out $@ BUILDTYPE=$(BUILDTYPE)
 endif
@@ -70,7 +70,7 @@ endif
 local_filenames := $(shell ls)
 .PHONY: $(local_filenames)
 $(local_filenames)::
-	./gyp_skia
+	$(CWD)/gyp_skia
 ifneq (,$(findstring Linux, $(uname)))
 	$(MAKE) -C out $@ BUILDTYPE=$(BUILDTYPE)
 endif

gyp_skia

@@ -58,6 +58,13 @@ def additional_include_files(args=[]):
 if __name__ == '__main__':
   args = sys.argv[1:]
 
+  # Set CWD to the directory containing this script.
+  # This allows us to launch it from other directories, in spite of gyp's
+  # finickyness about the current working directory.
+  # See http://b.corp.google.com/issue?id=5019517 ('Linux make build
+  # (from out dir) no longer runs skia_gyp correctly')
+  os.chdir(script_dir)
+
   # This could give false positives since it doesn't actually do real option
   # parsing.  Oh well.
   gyp_file_specified = False
@@ -68,8 +75,10 @@ if __name__ == '__main__':
 
   # If we didn't get a file, then fall back to assuming 'skia.gyp' from the
   # same directory as the script.
+  # The gypfile must be passed as a relative path, not an absolute path,
+  # or else the gyp code doesn't write into the proper output dir.
   if not gyp_file_specified:
-    args.append(os.path.join(script_dir, 'skia.gyp'))
+    args.append('skia.gyp')
 
   args.extend(['-I' + i for i in additional_include_files(args)])
   args.extend(['--depth', '.'])