branch master updated (8f98581 -> 4ed64c5)

[Danny Milosavljevic]

dannym pushed a change to branch master
in repository guix.

      from  8f98581   gnu: libpng-apng: Remove unnecessary call to libtool.
       new  b0dcb52   gnu: rust: Update to 1.15.0.
       new  893bc3f   gnu: cargo: Use upstream cargo.
       new  25fb58a   build-system/cargo (cargo-build): Add cargo-build-flags, 
remove configure-flags.
       new  4ed64c5   build/cargo-build-system: Make cargo-build-system install 
working packages.

The 4 revisions listed above as "new" are entirely new to this
repository and will be described in separate emails.  The revisions
listed as "adds" were already present in the repository and have only
been added to this reference.


Summary of changes:
 gnu/packages/rust.scm             | 523 +++++++++++++++++++++++++++++++++++++-
 guix/build-system/cargo.scm       |   3 +-
 guix/build/cargo-build-system.scm | 116 +++++++--
 3 files changed, 610 insertions(+), 32 deletions(-)