https://bugs.gentoo.org/778332
https://github.com/proftpd/proftpd/commit/4ffe04158840130e023ed3d3e558b8d70e28e20e

From 2a15ce409f70c67ba9b1e09de67c3fca0b38eff8 Mon Sep 17 00:00:00 2001
From: orbea <orbea@riseup.net>
Date: Sun, 21 Mar 2021 12:38:52 -0700
Subject: [PATCH] build: Fix linking the static libsupp.a library.

---
 configure.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/configure.in
+++ b/configure.in
@@ -88,7 +88,7 @@ if test $ac_cv_prog_gcc = no -a "$OSTYPE" = "-DHPUX10"; then
   CFLAGS="$CFLAGS -Ae"
 fi
 
-LDFLAGS="-L\$(top_srcdir)/lib -L\$(top_builddir)/lib $LDFLAGS"
+LDFLAGS="-Wl,-L\$(top_srcdir)/lib,-L\$(top_builddir)/lib $LDFLAGS"
 
 # AIX has issues with the -rdynamic linker flag.  How many different AIX
 # versions should we support here?
--- a/configure
+++ b/configure
@@ -14932,7 +14944,7 @@ if test $ac_cv_c_compiler_gnu = no -a "$OSTYPE" = "-DHPUX10"; then
   CFLAGS="$CFLAGS -Ae"
 fi
 
-LDFLAGS="-L\$(top_srcdir)/lib -L\$(top_builddir)/lib $LDFLAGS"
+LDFLAGS="-Wl,-L\$(top_srcdir)/lib,-L\$(top_builddir)/lib $LDFLAGS"
 
 # AIX has issues with the -rdynamic linker flag.  How many different AIX
 # versions should we support here?