diff --git a/configure.in b/configure.in
index 3f158b0eab..500f3eb727 100644
--- a/configure.in
+++ b/configure.in
@@ -514,10 +514,13 @@ AC_ARG_ENABLE(timerfd-wrapper,
 [AC_HELP_STRING([--enable-timerfd-wrapper],[timerfd is in the kernel but not in your libc])],[enable_timer_fd_wrapper="$enableval"],[enable_timer_fd_wrapper="no"])
 AM_CONDITIONAL([ENABLE_TIMERFD_WRAPPER],[test "x$enable_timer_fd_wrapper" != "xno"])
 
+ESL_LDFLAGS=
+PLATFORM_CORE_LDFLAGS=
+PLATFORM_CORE_LIBS=
 
 AC_CHECK_LIB(z, inflateReset, have_libz=yes, AC_MSG_ERROR([no usable zlib; please install zlib devel package or equivalent]))
 if test "x$have_libz" = "xyes"  ; then
-APR_ADDTO(SWITCH_AM_LDFLAGS, -lz)
+APR_ADDTO([PLATFORM_CORE_LIBS], [-lz])
 fi
 
 AC_CHECK_LIB(jpeg, jpeg_std_error,, AC_MSG_ERROR([no usable libjpeg; please install libjpeg devel package or equivalent]))
@@ -539,9 +542,6 @@ if test "x$have_libresolv" = "xyes"  ; then
 APR_ADDTO(SWITCH_AM_LDFLAGS, -lresolv)
 fi
 
-ESL_LDFLAGS=
-PLATFORM_CORE_LDFLAGS=
-PLATFORM_CORE_LIBS=
 # tweak platform specific flags
 case "$host" in
     *darwin12.*|*darwin11.*)