gh-110459: Make sure --with-openssl-rpath works on macOS (#113441)

* gh-110459: Make sure --with-openssl-rpath works on macOS

On macOS the `-rpath` linker flag is spelled differently
than on on platforms.

Author: ronaldoussoren

Misc/NEWS.d/next/macOS/2023-12-23-22-41-07.gh-issue-110459.NaMBJy.rst

@@ -0,0 +1,2 @@
+Running ``configure ... --with-openssl-rpath=X/Y/Z`` no longer fails to detect
+OpenSSL on macOS.

configure

@@ -6808,7 +6808,12 @@ AX_CHECK_OPENSSL([have_openssl=yes],[have_openssl=no])
 AS_VAR_IF([GNULD], [yes], [
   rpath_arg="-Wl,--enable-new-dtags,-rpath="
 ], [
-  rpath_arg="-Wl,-rpath="
+  if test "$ac_sys_system" = "Darwin"
+  then
+     rpath_arg="-Wl,-rpath,"
+  else
+     rpath_arg="-Wl,-rpath="
+  fi
 ])
 
 AC_MSG_CHECKING([for --with-openssl-rpath])