build: Use LDADD instead of LDFLAGS for libcommon.la.

[orbea]

When building pdsh with slibtool (https://dev.midipix.org/cross/slibtool) it fails with many undefined references.

This is because of this command-line:

clang ../../src/common/.libs/libcommon.a main.o dsh.o mod.o rcmd.o opt.o 
privsep.o pcp_server.o pcp_client.o testcase.o wcoll.o cbuf.o config.o -O3 
-Wall -fno-strict-aliasing -ldl -s -pthread -o .libs/pdsh.inst -Wl,--export-dynamic

While with GNU libtool it works.

clang -O3 -Wall -fno-strict-aliasing -s -pthread -o pdsh.inst main.o dsh.o 
mod.o rcmd.o opt.o privsep.o pcp_server.o pcp_client.o testcase.o wcoll.o 
cbuf.o config.o -Wl,--export-dynamic  -ldl ../../src/common/.libs/libcommon.a -pthread

This is because by chance GNU libtool orders ../../src/common/.libs/libcommon.a at the end while slibtool places it at the beginning. This happens because src/pdsh/Makefile.am uses LDFLAGS instead of LDADD for ../../src/common/.libs/libcommon.a, when using LDADD instead it is explicitly placed at the end and the build succeeds.

Here is a build log for reference: pdsh.slibtool.log
GNU libtool log: pdsh.libtool.log

Also see this downstream issue: https://bugs.gentoo.org/775593

[grondo]

Sorry for leaving this to languish!

This change looks good to me. Do you mind if I rebase to get CI checks to run (though I don't anticipate any problems, we like to rebase and merge anyway)

Approving reviews have been dismissed because this pull request
was updated.

[orbea]

Do you mind if I rebase to get CI checks to run

I don't mind at all, but I rebased it myself since that was low effort.

[grondo]

Excellent, thanks!

[codecov-commenter]

Codecov Report

Merging #130 (49dfc7d) into master (228a1ca) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #130   +/-   ##
=======================================
  Coverage   63.81%   63.81%           
=======================================
  Files          27       27           
  Lines        5585     5585           
=======================================
  Hits         3564     3564           
  Misses       2021     2021           

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[grondo]

LGTM, and thanks for the fix!