RFR: 8351322: Parameterize link option for pthreads

[snake66]

On Thu, 6 Mar 2025 14:15:38 GMT, Erik Joelsson <erikj at openjdk.org> wrote:

>> Replace hardcoded instances of `-lpthread` with `$(LIBPTHREAD)`, so that it's possible to parameterize this for platforms that use different flags for enabling posix threads.
>> 
>> This work is a continuation of the work done by Greg Lewis in [1], but generalized for the full JDK, and set at the configure stage.
>> 
>> Sponsored by: The FreeBSD Foundation
>> Co-authored-by: Greg Lewis <glewis at eyesbeyond.com>
>> 
>> [1]: https://github.com/battleblow/jdk23u/commit/dbd90aa8ab0b7f5e4865864a7c63d975daacabf4
>
> make/autoconf/libraries.m4 line 142:
> 
>> 140:   # Threading library
>> 141:   if test "x$OPENJDK_TARGET_OS" = xlinux || test "x$OPENJDK_TARGET_OS" = xaix; then
>> 142:     BASIC_JVM_LIBS="$BASIC_JVM_LIBS $(LIBPTHREAD)"
> 
> If you specifically need this to be resolved in the makefile rather than here, then please add a comment explaining why, otherwise use a shell script variable reference.
> 
> Suggestion:
> 
>     BASIC_JVM_LIBS="$BASIC_JVM_LIBS $LIBPTHREAD"

@erikj79 There will be a later patch to libraries.m4 that sets the variable based on the target platform, and then populates the `LIBPTHREAD` variable in spec.gmk. (https://github.com/openjdk/jdk/pull/23930/files#diff-56172cd2ec5804a5f764a6d0d5970da6144b024a06e008571f9822b2dc83cc36R147) That means the parenthesis should stay, right?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/23930#discussion_r1983779126