build: fix build with BSD 'make' implementations

On FreeBSD, NetBSD, and OpenBSD 'make' fails with an error similar to
the following:

    $ make
    make  all-recursive
    Making all in po
    make[2]: don't know how to make ./lib/libhello.a. Stop

    make[2]: stopped making "all-am" in /usr/home/collinfunk/hello
    *** Error code 1
    [...]

This is because the target lacks the "./" prefix that is in the
dependency.

* NEWS: Mention the improvement.
* Makefile.am (hello_LDADD): Remove $(top_builddir) prefix.

diff --git a/Makefile.am b/Makefile.am
line changes: +1/-1
index 6f9556b..d1fc912
--- a/Makefile.am
+++ b/Makefile.am

@@ -35,7 +35,7 @@ SUBDIRS = po
 bin_PROGRAMS = hello
 hello_SOURCES = src/hello.c src/system.h
 
-hello_LDADD = $(top_builddir)/lib/lib$(PACKAGE).a \
+hello_LDADD = lib/lib$(PACKAGE).a \
 	$(HARD_LOCALE_LIB) \
 	$(LIBC32CONV) \
 	$(LIBICONV) \

diff --git a/NEWS b/NEWS
line changes: +4/-0
index 176baaf..54a755f
--- a/NEWS
+++ b/NEWS

@@ -7,6 +7,10 @@ removed in release 2.11.
 
 Update gnulib for compatibility with glibc-2.43.
 
+GNU hello no longer fails to build with BSD implementations of the
+'make' command.  Previously they would be unable to find a target
+required listed as a dependency of the 'hello' program.
+
 * Noteworthy changes in release 2.12.2 (2025-05-19) [stable]
 
 Update gnulib, and support latest versions of automake and autoconf.