Toolchains update

Hi,

   while toying around build system for Odroid C1 I saw that toolchains for arm-linux-gnueabihf where "old" as we are at "gcc-linaro-7.2.1-2017.11-x86_64_arm-linux-gnueabihf" since the 7.3.1 looks like it is not available for this platform.

So I did some changes in lib/general.sh and added the following as a fast hack:

"https://releases.linaro.org/components/toolchain/binaries/7.4-2019.02/arm-linux-gnueabihf/gcc-linaro-7.4.1-2019.02-x86_64_arm-linux-gnueabihf.tar.xz"
"https://developer.arm.com/-/media/Files/downloads/gnu-a/8.2-2019.01/gcc-arm-8.2-2019.01-x86_64-arm-linux-gnueabihf.tar.xz"

Then I modified the configuration files for odroidc1 to test both toolchains (namely config/sources/odroidc1.conf) and I produced working images with both toolchains.

Personally (but without any scientific approach) I saw:

• 7.4.1 it looked like very slow to compile... maybe my system was busy doing other things maybe not
• 8.2 produced a smaller kernel (with same .config) and its speed was acceptable

Is there a reason that arm-linux-gnueabihf is stil at 7.2.1 (2017.11)?

Thanks in advance

*Bye

Piero