[Buildroot] [git commit branch/2018.02.x] support/graph-depends: fix package names starting with a non-alpha

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=81c273d1744995a89247b26294492ba7c17d096b
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2018.02.x

Graphviz' dot utility does not like nodes which names does not start
with an ^[[:alpha:]], i.e. 18xx-ti-utils would cause grievance:

    Warning: syntax ambiguity - badly delimited number '18x' in line 4 [...]/graph-depends.dot splits into two tokens
    Warning: syntax ambiguity - badly delimited number '18x' in line 5 [...]/graph-depends.dot splits into two tokens
    Warning: syntax ambiguity - badly delimited number '18x' in line 6 [...]/graph-depends.dot splits into two tokens
    Warning: syntax ambiguity - badly delimited number '18x' in line 7 [...]/graph-depends.dot splits into two tokens

Prefix nodes with an underscore to fix that.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
(cherry picked from commit 020206ca5784ca60fd72c7ff0aea6557d1d9bf6e)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 support/scripts/graph-depends | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/support/scripts/graph-depends b/support/scripts/graph-depends
index 85c9bf0a4f..51b69c44c0 100755
--- a/support/scripts/graph-depends
+++ b/support/scripts/graph-depends
@@ -183,9 +183,10 @@ def get_all_depends(pkgs):
 
 
 # The Graphviz "dot" utility doesn't like dashes in node names. So for
-# node names, we strip all dashes.
+# node names, we strip all dashes. Also, nodes can't start with a number,
+# so we prepend an underscore.
 def pkg_node_name(pkg):
-    return pkg.replace("-", "")
+    return "_" + pkg.replace("-", "")
 
 
 TARGET_EXCEPTIONS = [