Add gcc to the prequisites list

[samuel-rubin]

I was looking at my logs for a sanity.system test and I noticed that it used GCC. I then went to the prerequisites list and I noticed that GCC was not listed. Can you please update the prerequisite list to indicate that GCC is required and which version is needed if applicable? Related to eclipse/openj9#4208

[Mesbah-Alam]

GCC is required to build the 'native' system tests, yes. So, I do agree that we should add it in the prerequisite list. However, I am not sure if there is any specific version (or later than that) must be present to compile the native system tests. They have traditionally had no problems with whatever GCC the test machine comes with.

@lumpfish - any comment?

[Mesbah-Alam]

Equivalent issue in openj9-systemtest: https://github.com/eclipse/openj9-systemtest/issues/82

[lumpfish]

Microsoft Visual Studio is required for Windows, gcc for all other platforms. The build never added a prereq target to install gcc because all the systems it was originally developed on (and since then, other than via this issue) had a gcc installed. So there is no defined minimum gcc level required for the native test cases to build. They will have been built in the past with versions which predate anything installed on today's machines. I think I'd leave the openjdk-systemtest build as is - i.e. assume a gcc is present. A build / test machine will typically have a gcc installed on it anyway (to build the jdk) - that level (required for building the jdk) will be adequate for building the native system test cases.