readline: define NEED_EXTERN_PC for static linking

tells readline to use the PC variable from libtermcap instead of
defining its own. This fixes the multiple definition error when
attempting to statically link readline

Signed-off-by: Christopher Degawa <ccom@randomderp.com>

mingw-w64-readline/PKGBUILD

@@ -6,7 +6,7 @@ pkgname="${MINGW_PACKAGE_PREFIX}-${_realname}"
 _basever=8.2
 _patchlevel=001
 pkgver=${_basever}.${_patchlevel}
-pkgrel=5
+pkgrel=6
 pkgdesc="MinGW port of readline for editing typed command lines (mingw-w64)"
 arch=('any')
 mingw_arch=('mingw32' 'mingw64' 'ucrt64' 'clang64' 'clang32' 'clangarm64')
@@ -71,6 +71,7 @@ prepare() {
 build() {
   [[ -d ${srcdir}/build-${MSYSTEM} ]] && rm -rf ${srcdir}/build-${MSYSTEM}
   mkdir -p ${srcdir}/build-${MSYSTEM} && cd ${srcdir}/build-${MSYSTEM}
+  export CFLAGS="$CFLAGS -DNEED_EXTERN_PC=1" # Use extern PC variable from libtermcap
   ../${_realname}-${_basever}/configure \
     --prefix=${MINGW_PREFIX} \
     --host=${MINGW_CHOST} \