[GUILT 1/5] Fix generation of Documentation/usage-%.txt.

[Per Cederqvist <cederp@opera.com>]

The old rule worked, most of the time, but had several issues:

 - It depended on the corresponding guilt-*.txt file, but the usage.sh
   script actually reads ../guilt-foo.

 - Actually, each usage-%.txt depended on all guilt-*.txt files, so
   make had to do more work than necessary if a single file was
   altered.

 - The construct broke parallel make, which would spawn several
   usage.sh at once.  This leads to unnecessary work, and could
   potentially result in broken usage files if the "echo some_string >
   some_file" construct used by usage.sh isn't atomic.

Fixed by letting the usage.sh script update a single file, and writing
a proper implicit make rule.  This makes parallel make work a lot
better.

There is a small downside, though, as usage.sh will now be run once
for each command (if everything is regenerated).  I think it is worth
to pay that price to get the correctness.  This command is still very
fast compared to the docbook processing.

Signed-off-by: Per Cederqvist <cederp@opera.com>
---
 Documentation/Makefile | 4 ++--
 Documentation/usage.sh | 8 +++-----
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index b6c3285..ec3c9e8 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -66,8 +66,8 @@ clean:
 	rm -f usage-*.txt
 	rm -f version.txt
 
-usage-%.txt: $(MAN1_TXT) usage.sh
-	sh ./usage.sh
+usage-guilt-%.txt: ../guilt-% usage.sh
+	sh ./usage.sh $<
 
 %.html : %.txt footer.txt version.txt
 	$(ASCIIDOC) -b xhtml11 -d manpage -f asciidoc.conf $(ASCIIDOC_EXTRA) $<
diff --git a/Documentation/usage.sh b/Documentation/usage.sh
index 20fdca4..629f546 100644
--- a/Documentation/usage.sh
+++ b/Documentation/usage.sh
@@ -1,7 +1,5 @@
 #!/bin/sh
 
-for i in `ls ../guilt-*`; do
-	name=$(basename $i)
-	u=$(grep USAGE $i |  sed 's/USAGE="//' | sed 's/"$//') 
-	echo "'$name' $u"  > usage-$name.txt
-done
+name=$(basename $1)
+u=$(grep USAGE $1 |  sed 's/USAGE="//' | sed 's/"$//') 
+echo "'$name' $u"  > usage-$name.txt
-- 
2.1.0