[PATCH v2 10b/16] engine.pl: delete the captured stderr file if empty

[Philip Oakley <philipoakley@iee.org>]

Keep the build clean of extraneous files if it is indeed clean.
Otherwise leave the msvc-build-makedryerrors.txt file both as
a flag for any CI system or for manual debugging.

Alternatively, with improved syntactic sugar[1]:
	unlink $ErrsFile if -f -z $ErrsFile;
could be used but requires Perl 5.10 or later, which is not
available on Msysgit, but is available on the newer Git-for-Windows
SDK on Msys2 [2].

Note that the file will contain the new values of the GIT_VERSION
and GITGUI_VERSION if they were generated by the make file. They
are omitted if the release is tagged and identically defined in
their respective GIT_VERSION_GEN file DEF_VER variables.

[1]: http://perldoc.perl.org/functions/-X.html
[2]: http://git-for-windows.github.io/

Helped-by:  Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Philip Oakley <philipoakley@iee.org>
---
Eric's help gmane.comp.version-control.msysgit/21745
---
 contrib/buildsystems/engine.pl | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/contrib/buildsystems/engine.pl b/contrib/buildsystems/engine.pl
index a6999b6..154575d 100755
--- a/contrib/buildsystems/engine.pl
+++ b/contrib/buildsystems/engine.pl
@@ -77,6 +77,8 @@ EOM
 
 my $ErrsFile = "msvc-build-makedryerrors.txt";
 @makedry = `cd $git_dir && make -n MSVC=1 V=1 2>$ErrsFile` if !@makedry;
+# test for an empty Errors file and remove it
+unlink $ErrsFile if -f $ErrsFile && -z _;
 
 # Parse the make output into usable info
 parseMakeOutput();
-- 
2.3.1