bitcoin: Add comment explaining pre-configure

[Greg Troxel <gdt%ir.bbn.com@localhost>]

Module Name:	pkgsrc-wip
Committed By:	Greg Troxel <gdt%ir.bbn.com@localhost>
Pushed By:	gdt
Date:		Mon Nov 28 13:15:57 2016 -0500
Changeset:	298fd12c80a53e068d634b51b1551c6f21ae8cc2

Modified Files:
	bitcoin/Makefile

Log Message:
bitcoin: Add comment explaining pre-configure

To see a diff of this commit:
https://wip.pkgsrc.org/cgi-bin/gitweb.cgi?p=pkgsrc-wip.git;a=commitdiff;h=298fd12c80a53e068d634b51b1551c6f21ae8cc2

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

diffstat:
 bitcoin/Makefile | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diffs:
diff --git a/bitcoin/Makefile b/bitcoin/Makefile
index e7f844c..2c52fdc 100644
--- a/bitcoin/Makefile
+++ b/bitcoin/Makefile
@@ -58,11 +58,11 @@ SUBST_STAGE.pkg= 	post-patch
 SUBST_SED.pkg=		-e "s|/usr/|${PREFIX}/|g"
 SUBST_MESSAGE.pkg=	"Fixing dirs."
 
-# TODO: explain why this is necessary versus some more compact
-# invocation
+# bitcoin does not actually have releases; only snapshots of the
+# repository from which a release would have been made.  Remedially
+# create configure.in and similar.
 pre-configure:
-	cd ${WRKSRC};             \
-	./autogen.sh
+	cd ${WRKSRC} && ./autogen.sh
 
 # TODO: explain why this is necessary
 # TODO: explain why bitcoint-qt is commented out