package/mpd: fix iconv detection w/ libiconv installed

Fix build failures caused by meson failing to properly detect iconv() when
libiconv is installed and a missing link dependency.

Upstream pull request:
https://github.com/MusicPlayerDaemon/MPD/pull/1515

Fixes the following build failures:
http://autobuild.buildroot.net/results/7a0/7a0fe4e9248ed96a5c4934361de16e0b59a51d50/

Signed-off-by: Andreas Ziegler <br015@umbiko.net>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/mpd/0002-src-lib-icu-fix-iconv-detection-when-libiconv-is-ins.patch

@@ -0,0 +1,53 @@
+From 3882a5a263caa681778a21b1f5f13a1b64536796 Mon Sep 17 00:00:00 2001
+From: aeolio <git@aeolio.de>
+Date: Wed, 20 Apr 2022 16:10:39 +0200
+Subject: [PATCH] src/lib/icu: fix iconv() detection when libiconv is installed
+
+Signed-off-by: aeolio <git@aeolio.de>
+Upstream: https://github.com/MusicPlayerDaemon/MPD/pull/1515
+Signed-off-by: Andreas Ziegler <br015@umbiko.net>
+---
+ src/lib/icu/meson.build | 11 +++++++++--
+ 1 file changed, 9 insertions(+), 2 deletions(-)
+
+diff --git a/src/lib/icu/meson.build b/src/lib/icu/meson.build
+index 59215e704..972c1fda3 100644
+--- a/src/lib/icu/meson.build
++++ b/src/lib/icu/meson.build
+@@ -12,17 +12,23 @@ if is_windows
+   icu_sources += 'Win32.cxx'
+ endif
+ 
++iconv_dep = []
+ if icu_dep.found()
+   icu_sources += [
+     'Util.cxx',
+     'Init.cxx',
+   ]
+ elif not get_option('iconv').disabled()
+-  have_iconv = compiler.has_function('iconv', prefix : '#include <iconv.h>')
+-  conf.set('HAVE_ICONV', have_iconv)
++  # an installed iconv library will make the builtin iconv() unavailable,
++  # so search for the library first and pass it as (possible) dependency
++  iconv_dep = compiler.find_library('libiconv', required: false)
++  have_iconv = compiler.has_function('iconv', 
++    dependencies: iconv_dep, 
++    prefix : '#include <iconv.h>')
+   if not have_iconv and get_option('iconv').enabled()
+     error('iconv() not available')
+   endif
++  conf.set('HAVE_ICONV', have_iconv)
+ endif
+ 
+ icu = static_library(
+@@ -31,6 +37,7 @@ icu = static_library(
+   include_directories: inc,
+   dependencies: [
+     icu_dep,
++    iconv_dep,
+     fmt_dep,
+   ],
+ )
+-- 
+2.34.1
+