Commit 67ebacb for zlib

commit 67ebacb61f15fceeb8638546eb54a899edd54341
Author: Mark Adler <git@madler.net>
Date:   Mon Nov 2 17:32:57 2026 -0800

    Avoid undefined symbols warnings when compiling solo.

diff --git a/configure b/configure
index b0eab5f..7bc0f6d 100755
--- a/configure
+++ b/configure
@@ -544,11 +544,14 @@ if test $shared -eq 1; then
   echo Checking for shared library support... | tee -a configure.log
   # we must test in two steps (cc then ld), required at least on SunOS 4.x
   # the second link test is for linkers like lld that by default reject a
-  # version script naming symbols that the test object doesn't define
+  # version script naming symbols that the test object doesn't define -- if
+  # that's needed, keep the option, since some builds (e.g. --solo) don't
+  # define all of the symbols in zlib.map
   if try $CC -c $SFLAGS $test.c &&
      { try $LDSHARED $SFLAGS $LDFLAGS -o $test$shared_ext $test.o ||
-       try $LDSHARED $SFLAGS $LDFLAGS -Wl,--undefined-version \
-           -o $test$shared_ext $test.o; }; then
+       { try $LDSHARED $SFLAGS $LDFLAGS -Wl,--undefined-version \
+             -o $test$shared_ext $test.o &&
+         LDSHARED="$LDSHARED -Wl,--undefined-version"; }; }; then
     echo Building shared library $SHAREDLIBV with $CC. | tee -a configure.log
   elif test -z "$old_cc" -a -z "$old_cflags"; then
     echo No shared library support. | tee -a configure.log