RFR: 8323667: Library debug files contain non-reproducible full gcc include paths

[Erik Joelsson]

On Fri, 12 Jan 2024 14:33:01 GMT, Andrew Leonard <aleonard at openjdk.org> wrote:

> For gcc toolchains in ALLOW_ABSOLUTE_PATHS_IN_OUTPUT=False builds, this PR finds the location of the gcc system include paths, and adds -fdebug-prefix-map flags to map them to a standard location. Thus making the debuginfo and resulting libraries reproducible when using DevKits in different path locations.

make/autoconf/flags-cflags.m4 line 193:

> 191: 
> 192:     # Add gcc system include mapping => /usr/local/gcc_include
> 193:     #   Find location of stddef.h using build C compiler

Why use the build compiler here?

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PR Review Comment: https://git.openjdk.org/jdk/pull/17399#discussion_r1450586473