libssh2: autoreconf for libtool linking of dll

Patch configure.ac to fix error trying to undefine an undefined macro.

mingw-w64-libssh2/PKGBUILD

@@ -4,7 +4,7 @@ _realname=libssh2
 pkgbase=mingw-w64-${_realname}
 pkgname="${MINGW_PACKAGE_PREFIX}-${_realname}"
 pkgver=1.9.0
-pkgrel=2
+pkgrel=3
 pkgdesc="A library implementing the SSH2 protocol as defined by Internet Drafts (mingw-w64)"
 arch=('any')
 mingw_arch=('mingw32' 'mingw64' 'ucrt64')
@@ -16,13 +16,17 @@ depends=("${MINGW_PACKAGE_PREFIX}-openssl"
          "${MINGW_PACKAGE_PREFIX}-zlib")
 options=('staticlibs' 'strip')
 source=("${url}/download/${_realname}-${pkgver}.tar.gz"
-        fix-pkgconfig.patch)
+        fix-pkgconfig.patch
+        fix-configure-ac.patch)
 sha256sums=('d5fb8bd563305fd1074dda90bd053fb2d29fc4bce048d182f96eaa466dfadafd'
-            '7a6545f6d457ad008aacefe04a60727c02d33927c8a903745bf191f69cc8ba55')
+            '7a6545f6d457ad008aacefe04a60727c02d33927c8a903745bf191f69cc8ba55'
+            '956b2518618646f9134f0eee7c539ebfb3ddeeff48019831b53997464edbf4f1')
 
 prepare() {
   cd ${_realname}-${pkgver}
   patch -p1 -i ${srcdir}/fix-pkgconfig.patch
+  patch -p1 -i ${srcdir}/fix-configure-ac.patch
+  autoreconf -fi
 }
 
 build() {

mingw-w64-libssh2/fix-configure-ac.patch

@@ -0,0 +1,11 @@
+--- libssh2-1.9.0/configure.ac.ORIG	2021-04-12 11:23:19.331827300 -0700
++++ libssh2-1.9.0/configure.ac	2021-04-12 11:23:59.738111400 -0700
+@@ -127,8 +127,6 @@
+ m4_set_foreach([crypto_backends], [backend],
+   [AM_CONDITIONAL(m4_toupper(backend), test "$found_crypto" = "backend")]
+ )
+-m4_undefine([backend])
+-
+ 
+ # libz
+