gitweb/Makefile: conditionally include ../GIT-VERSION-FILE

The 'clean' target is still noticeably slow on cygwin, despite the
improvements made by previous patches. For example, the second
invocation of 'make clean' below:

  $ make clean >/dev/null 2>&1
  $ make clean
  ...
  make[1]: Entering directory '/home/ramsay/git/gitweb'
  make[2]: Entering directory '/home/ramsay/git'
  make[2]: 'GIT-VERSION-FILE' is up to date.
  make[2]: Leaving directory '/home/ramsay/git'
  ...
  $

has been timed at 10.361s on my laptop (an old core i5-4200M @ 2.50GHz,
8GB RAM, 1TB HDD).

Notice that the 'clean' target is making a nested call to the parent
Makefile to ensure that the GIT-VERSION-FILE is up-to-date. This is to
ensure that the $(GIT_VERSION) make variable is set, once that file had
been included. However, the 'clean' target does not use the $(GIT_VERSION)
variable, directly or indirectly, so it does not have any affect on what
the target removes. Therefore, the time spent on ensuring an up to date
GIT-VERSION-FILE is wasted effort.

In order to eliminate such wasted effort, use the value of the internal
$(MAKECMDGOALS) variable to only '-include ../GIT-VERSION-FILE' when the
target is not 'clean'. (This drops the time down to 8.430s, on my laptop,
giving an improvement of 18.64%).

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/gitweb/Makefile b/gitweb/Makefile
index cd194d057f..f13e23c4de 100644
--- a/gitweb/Makefile
+++ b/gitweb/Makefile
@@ -48,7 +48,9 @@ HIGHLIGHT_BIN = highlight
 ../GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE
 	$(QUIET_SUBDIR0)../ $(QUIET_SUBDIR1) GIT-VERSION-FILE
 
+ifneq ($(MAKECMDGOALS),clean)
 -include ../GIT-VERSION-FILE
+endif
 
 ### Build rules