package libidn: add "-liconv" to libidn.pc

This is necessary for static linking, as demonstrated by the test
program that this patch also adds.

src/libidn-1-fix-pc.patch

@@ -0,0 +1,14 @@
+This file is part of mingw-cross-env.
+See doc/index.html for further information.
+
+Hack to use pkg-config with static linking.
+
+--- a/libidn.pc.in
++++ b/libidn.pc.in
+@@ -19,5 +19,5 @@
+ Description: IETF stringprep, nameprep, punycode, IDNA text processing.
+ URL: http://www.gnu.org/software/libidn/
+ Version: @VERSION@
+-Libs: -L${libdir} -lidn
++Libs: -L${libdir} -lidn -liconv
+ Cflags: -I${includedir}

src/libidn-test.c

@@ -0,0 +1,20 @@
+/* This file is part of mingw-cross-env.       */
+/* See doc/index.html for further information. */
+
+#include <stdlib.h>
+#include <idna.h>
+
+int main(int argc, char *argv[])
+{
+    char *hostname_ascii;
+
+    (void)argc;
+    (void)argv;
+
+    if (idna_to_ascii_lz("www.google.com", &hostname_ascii, 0) == IDNA_SUCCESS)
+    {
+        free(hostname_ascii);
+    }
+
+    return 0;
+}

src/libidn.mk

@@ -29,4 +29,9 @@ define $(PKG)_BUILD
         --prefix='$(PREFIX)/$(TARGET)' \
         --with-libiconv-prefix='$(PREFIX)/$(TARGET)'
     $(MAKE) -C '$(1)' -j '$(JOBS)' install bin_PROGRAMS= sbin_PROGRAMS= noinst_PROGRAMS=
+
+    '$(TARGET)-gcc' \
+        -W -Wall -Werror -ansi -pedantic \
+        '$(2).c' -o '$(PREFIX)/$(TARGET)/bin/test-libidn.exe' \
+        `'$(TARGET)-pkg-config' libidn --cflags --libs`
 endef