gnu: sablevm: Build reproducibly.

* gnu/packages/java.scm (sablevm)[arguments]: Add build phase
"remove-timestamp-for-reproducibility".

gnu: sablevm: Do not use bundled libraries.

* gnu/packages/java.scm (sablevm)[inputs]: Add popt and libffi.
[arguments]: Add configure flags and build phase to avoid using bundled
libraries.

gnu: classpath-devel: Ensure initial heap size is less than maximum.

Fixes <https://bugs.gnu.org/27142>.

* gnu/packages/java.scm (classpath-devel)[arguments]: Pass Xms option with a
value lower than Xmx.

Merge branch 'master' into staging

gnu: ant: Implement in terms of ant/java8.

* gnu/packages/java.scm (ant): Inherit from ant/java8.

gnu: Add ant/java8.

* gnu/packages/java.scm (ant/java8): New variable.

gnu: ant: Move after bootstrap packages.

* gnu/packages/java.scm (ant): Move package.

gnu: ant: Delete bundled jars.

* gnu/packages/java.scm (ant)[source]: Delete bundled jars in a snippet.

gnu: ant: Inherit from ant-bootstrap.

* gnu/packages/java.scm (ant)[build-system]
[home-page][synopsis][description][license]: Remove fields.
[arguments]: Adapt arguments of ant-bootstrap package.

gnu: clojure: Move below bootstrap packages.

* gnu/packages/java.scm (clojure): Move package.

gnu: java-swt: Move below the bootstrap packages.

* gnu/packages/java.scm (java-swt): Move the package.

gnu: icedtea-7: Use icedtea-6 for bootstrapping.

* gnu/packages/java.scm (icedtea-7)[source]: Remove Makefile.in patch to link
with GCJ libs.
[arguments]: Remove (ice-9 rdelim) module; adjust configure flags; do not add
GCJ headers to CPATH in build phase "set-additional-paths".
[native-inputs]: Remove gcj and ant; add icedtea-6 and ant-bootstrap.  Remove
autoconf and automake.
(icedtea-8)[native-inputs]: Delete "icedtea" from the inherited inputs, not
"gcj".

gnu: Add icedtea-6.

* gnu/packages/java.scm (icedtea-6): New variable.

gnu: Add ecj-javac-on-jamvm-wrapper-final.

* gnu/packages/java.scm (ecj-javac-on-jamvm-wrapper-final): New variable.

gnu: Add jamvm.

* gnu/packages/java.scm (jamvm): New variable.

gnu: Add classpath-devel.

* gnu/packages/java.scm (classpath-devel): New variable.

gnu: Add ecj-javac-on-jamvm-wrapper.

* gnu/packages/java.scm (ecj-javac-on-jamvm-wrapper): New variable.

gnu: Add classpath-jamvm-wrappers.

* gnu/packages/java.scm (classpath-jamvm-wrappers): New variable.

gnu: Add jamvm-bootstrap.

* gnu/packages/java.scm (jamvm-bootstrap): New variable.

gnu: Add classpath.

* gnu/packages/java.scm (classpath): New variable.