package/openjdk: needs host gcc >= 4.9

openjdk needs host gcc >= 4.9 since bump to version 16.0.1+9 in commit
057e2702 and
https://github.com/openjdk/jdk/commit/2a8f92e7e71f7c1ed4010fa31f4b413758c8752a:

configure: Using gcc BuildC compiler version 4.8.5 [cc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)]
configure: Using gcc BuildC++ compiler version 4.8.5 [g++ (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)]
configure: Using gcc build linker version 2.27 [GNU ld version 2.27-44.base.el7]

[...]

g++: error: unrecognized command line option '-std=c++14'

Add a dependency on host gcc >= 4.9 for the OpenJDK 16 version only, so
that users can still use OpenJDK 11 on older distributions.

Fixes:
 - http://autobuild.buildroot.org/results/7072308d148ccb8237180729551df65c87a76f11



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[yann.morin.1998@free.fr: limit the dependency to OpenJDK 16]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>