Index: configure.ac
--- configure.ac.orig
+++ configure.ac
@@ -735,6 +735,11 @@ AS_CASE([$CC,$host],
 )
 
 
+# Respect LDFLAGS and CFLAGS
+common_cflags="$common_cflags $CFLAGS"
+oc_ldflags="$oc_ldflags $LDFLAGS"
+
+
 ## Program to use to install files
 AC_PROG_INSTALL
 
@@ -867,10 +872,10 @@ AS_IF([test x"$enable_shared" != "xno"],
     [[*-*-linux*|*-*-freebsd[3-9]*|*-*-freebsd[1-9][0-9]*\
     |*-*-openbsd*|*-*-netbsd*|*-*-dragonfly*|*-*-gnu*|*-*-haiku*]],
       [sharedlib_cflags="-fPIC"
+      oc_ldflags="$oc_ldflags -Wl,-E"
        AS_CASE([$CC,$host],
            [gcc*,powerpc-*-linux*], [mksharedlib="$CC -shared -mbss-plt"],
-           [mksharedlib="$CC -shared"])
-      oc_ldflags="$oc_ldflags -Wl,-E"
+           [mksharedlib="$CC -shared $oc_ldflags"])
       rpath="-Wl,-rpath,"
       mksharedlibrpath="-Wl,-rpath,"
       natdynlinkopts="-Wl,-E"
@@ -912,6 +917,7 @@ AS_IF([test x"$enable_shared" != "xno"],
     [earm*-*-netbsd*], [natdynlink=true],
     [aarch64-*-linux*], [natdynlink=true],
     [aarch64-*-freebsd*], [natdynlink=true],
+    [aarch64-*-openbsd*], [natdynlink=true],
     [riscv*-*-linux*], [natdynlink=true])])
 
 # Try to work around the Skylake/Kaby Lake processor bug.
@@ -1013,6 +1019,8 @@ AS_CASE([$host],
     [arch=arm64; system=linux],
   [aarch64-*-freebsd*],
     [arch=arm64; system=freebsd],
+  [aarch64-*-openbsd*],
+    [arch=arm64; system=openbsd],
   [x86_64-*-cygwin*],
     [arch=amd64; system=cygwin],
   [riscv64-*-linux*],