busybox: configuration disable rpc support inside inetd

the rpc support requires that the libc contains rpc features but it's not always the case. Normaly libtirpc may replace the rpc support of the libc, but busybox doesn't support libtirpc currently
expat: CC CFLAGS and LDFLAGS already defined as export

expat-makeflags redefined CC CFLAGS and LDFLAGS but it's useless and we found twice the contain of CFLAGS inside the build command.
e2fsprogs: versioning support
scripts: enable modification of Config Linaro VFP for platforms
scripts: toolchain path points to the parent of the bin directory
scripts: install file in sysroot with install-sysroot variable

example:
install-y:=foobar.sh
foobar.sh:copy=$(src)/foobar.sh
foobar.sh:install-sysroot=y

install foobar.sh inside $(rootfs) and $(sysroot)
zlib: simplification of configuration script
scripts: e2fsprogs new configuration name
scripts: missing configuration name for versionning support
libc: add support of musl libc

musl is a new embedded libc

this patch provides new configuration informations about the libc
libc: musl library make information
libc: musl versionning
toolchain: sourcery toolchain eabi
toolchain: sourcery toolchain eabi support
server: configuration script modification

checks the libc capacities and the needs for each server
video: configuration flags of several video frameworks