Add amd64-osx-gcc.mk platform file for the JIT

[nbhuiyan]

This is needed for building OpenJ9 with gcc when using older versions of
XCode.

amd64-osx-clang.mk is still going to be the default makefile used
unless "PLATFORM" environment variable is set.

Signed-off-by: Nazim Uddin Bhuiyan [email protected]

Closes: #3326

Note: You must set the PLATFORM variable as amd64-osx-gcc in order to make use of this makefile.

[nbhuiyan]

@babsingh agreed that he will set the PLATFORM variable in the JDK8 extensions repo

@0xdaryl @DanHeidinga fyi

[DanHeidinga]

@nbhuiyan See also the change in this PR to ensure that PRODUCT is set - #3215

Does that need to be changed to work with this?

[nbhuiyan]

@DanHeidinga, changes to runtime/compiler/makefile.ftl proposed in #3215 would prevent us from making use of this file and would not solve the problem with building using gcc on older XCode, as this would override whatever we set PLATFORM to and prevent building OpenJ9 with JDK8. One (hacky) way to deal with this is to check for the VERSION_MAJOR variable in makefile.ftl, and set PLATFORM to amd64-osx-gcc for version 8. This would also remove the need to set it in the jdk extensions or manually when building with JDK8. How do you think this can be handled?

[babsingh]

I incorporated runtime/compiler/build/platform/host/amd64-osx-gcc.mk in openj9. Set export PLATFORM := amd64-osx-gcc in the extension repo (custom-spec.gmk.in). Compiler option -Werror=header-guard wasn't used. JDK8 built properly on OSX.

[DanHeidinga]

Change looks fine to me. @nbhuiyan Can you remove the WIP?

[DanHeidinga]

lgtm. @0xdaryl any comments on this?

[DanHeidinga]

issue #36

[DanHeidinga]

Jenkins compile xlinux jdk8

[0xdaryl]

Posthumously looks fine to me.