[8u] RFR: 8219772: EXTRA_CFLAGS not being picked up for assembler files

[Severin Gehwolf]

Hi,

Could somebody please review this one-liner change for the 8u (OpenJDK)
build system? The issue at hand is that for assembler source files
extra C flags are not being passed to the compiler (GCC in the Linux
case). This is a problem for instrumented builds to facilitate checks
on produced binaries in terms of optimization flags and other build-
time invariants[1]. The patch doesn't affect builds without extra C-
flags. Thus, risk should be minimal.

This is an 8u-only change. The new build system in JDK 11 and up seems
to handle these cases correctly.

Bug: https://bugs.openjdk.java.net/browse/JDK-8219772
webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8219772/01/webrev/

Testing: Compiling with extra cflags, inspecting build logs for
assembler source files on Linux x86_64

Thoughts?

Thanks,
Severin

[1] https://developers.redhat.com/blog/2019/02/04/annocheck-examining-the-contents-of-binary-files/