Add dlfcn-win32 to third_party

third_party/dlfcn-win32/configure

+#!/bin/sh
+# dlfcn-win32 configure script
+#
+# Parts copied from FFmpeg's configure
+#
+
+set_all(){
+    value=$1
+    shift
+    for var in $*; do
+        eval $var=$value
+    done
+}
+
+enable(){
+    set_all yes $*
+}
+
+disable(){
+    set_all no $*
+}
+
+enabled(){
+    eval test "x\$$1" = "xyes"
+}
+
+disabled(){
+    eval test "x\$$1" = "xno"
+}
+
+show_help(){
+  echo "Usage: configure [options]"
+  echo "Options: [defaults in brackets after descriptions]"
+  echo "All \"enable\" options have \"disable\" counterparts"
+  echo
+  echo "  --help                    print this message"
+  echo "  --prefix=PREFIX           install in PREFIX [$prefix]"
+  echo "  --libdir=DIR              install libs in DIR [$libdir]"
+  echo "  --incdir=DIR              install includes in DIR [$incdir]"
+  echo "  --enable-shared           build shared libraries [no]"
+  echo "  --enable-static           build static libraries [yes]"
+  echo "  --enable-msvc             create msvc-compatible import lib [auto]"
+  echo "  --enable-stripping        strip shared library [yes]"
+  echo
+  echo "  --cc=CC                   use C compiler CC [$cc_default]"
+  echo "  --cross-prefix=PREFIX     use PREFIX for compilation tools [$cross_prefix]"
+  exit 1
+}
+
+die_unknown(){
+    echo "Unknown option \"$1\"."
+    echo "See $0 --help for available options."
+    exit 1
+}
+
+prefix="/mingw"
+libdir='${prefix}/lib'
+incdir='${prefix}/include'
+ar="ar"
+cc_default="gcc"
+ranlib="ranlib"
+strip="strip"
+
+DEFAULT="msvc
+"
+
+DEFAULT_NO="shared
+"
+
+DEFAULT_YES="static
+    stripping
+"
+
+CMDLINE_SELECT="$DEFAULT
+    $DEFAULT_NO
+    $DEFAULT_YES
+"
+
+enable  $DEFAULT_YES
+disable $DEFAULT_NO
+
+for opt do
+    optval="${opt#*=}"
+    case "$opt" in
+    --help)
+        show_help
+    ;;
+    --prefix=*)
+        prefix="$optval"
+    ;;
+    --libdir=*)
+        libdir="$optval"
+    ;;
+    --incdir=*)
+        incdir="$optval"
+    ;;
+    --cc=*)
+        cc="$optval"
+    ;;
+    --cross-prefix=*)
+        cross_prefix="$optval"
+    ;;
+    --enable-?*|--disable-?*)
+        eval `echo "$opt" | sed 's/--/action=/;s/-/ option=/;s/-/_/g'`
+        echo "$CMDLINE_SELECT" | grep -q "^ *$option\$" || die_unknown $opt
+        $action $option
+    ;;
+    *)
+        die_unknown $opt
+    ;;
+    esac
+done
+
+ar="${cross_prefix}${ar}"
+cc_default="${cross_prefix}${cc_default}"
+ranlib="${cross_prefix}${ranlib}"
+strip="${cross_prefix}${strip}"
+
+if ! test -z $cc; then
+    cc_default="${cc}"
+fi
+cc="${cc_default}"
+
+disabled shared && disabled static && {
+    echo "At least one library type must be set.";
+    exit 1;
+}
+
+# simple cc test
+cat > /tmp/test.c << EOF
+#include <windows.h>
+void function(void)
+{ LoadLibrary(NULL); }
+EOF
+echo testing compiler: $cc -shared -o /tmp/test.dll /tmp/test.c
+$cc -shared -o /tmp/test.dll /tmp/test.c
+
+test "$?" != 0 && {
+    echo "$cc could not create shared file with Windows API functions.";
+    echo "Make sure your MinGW system is working properly.";
+    exit 1;
+}
+
+if enabled msvc; then
+    disabled shared && {
+        echo "MSVC understands static libraries created by gcc."
+        echo "There's no need to create an import lib."
+        exit 1
+    }
+    lib /? > /dev/null 2>&1 /dev/null || {
+        echo "MSVC's lib command not found."
+        echo "Make sure MSVC is installed and its bin folder is in your \$PATH."
+        exit 1
+    }
+fi
+
+if ! enabled stripping; then
+    strip="@echo ignoring strip"
+fi
+
+if enabled shared; then
+    lib /? > /dev/null 2>&1 /dev/null && enable msvc || disable msvc
+fi
+
+enabled msvc && libcmd="lib" || libcmd="@echo ignoring lib"
+
+echo "# Automatically generated by configure" > config.mak
+echo "prefix=$prefix" >> config.mak
+echo "libdir=$libdir" >> config.mak
+echo "incdir=$incdir" >> config.mak
+echo "AR=$ar" >> config.mak
+echo "CC=$cc" >> config.mak
+echo "RANLIB=$ranlib" >> config.mak
+echo "STRIP=$strip" >> config.mak
+echo "BUILD_SHARED=$shared" >> config.mak
+echo "BUILD_STATIC=$static" >> config.mak
+echo "BUILD_MSVC=$msvc" >> config.mak
+echo "LIBCMD=$libcmd" >> config.mak
+
+echo "prefix: $prefix"
+echo "libdir: $libdir"
+echo "incdir: $incdir"
+echo "ar:     $ar"
+echo "cc:     $cc"
+echo "ranlib: $ranlib"
+echo "strip:  $strip"
+echo "static: $static"
+echo "shared: $shared"
+if enabled shared; then
+    echo "msvc:   $msvc";
+    echo "strip:  $stripping";
+fi