1 files changed, 28 insertions, 0 deletions
diff --git a/showdeps b/showdeps
new file mode 100644
index 0000000..f59aeca
--- /dev/null
+++ b/showdeps
@@ -0,0 +1,28 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+my @targets;
+my @keys;
+my %prereqs;
+
+$ENV{LANGUAGE} = "en_US";
+for (`make --debug=b -n`) {
+	next if not /Prerequisite `([^']+)' is newer than target `([^']+)'/;
+
+	# Don't consider prerequisites that are targets.
+	unless ($ARGV[0] and $ARGV[0] eq '-a') {
+		push @targets, $2 if not grep { $_ eq $2 } @targets;
+		next if grep { $_ eq $1 } @targets;
+	}
+
+	push @keys, $1 if not grep { $_ eq $1 } @keys;
+	push @{$prereqs{$1}}, $2 if not grep { $_ eq $2 } @{$prereqs{$1}};
+}
+
+if (@keys) {
+	print "---\n";
+	print "$_ -> @{$prereqs{$_}}\n" for @keys;
+	print "---\n";
+}