main/json-c0.12: temporary aport

we need a libjson-c.so.2 til we fully migrated to libjson-c.so.4 (from
json-c 0.13) This is because mkinitfs is installed on builders so they
can make relases and mkinitfs depends on cryptsetup which depends on
json-c. This means that we have a dependency installed for
so:libsjon.so.2 which holds back json-c-dev to install version 0.13.

We solve this by adding a temporary json-c0.12 which can provide
so:libjson-c.so.2.

main/json-c0.12/APKBUILD

@@ -0,0 +1,48 @@
+# Maintainer: Natanael Copa <ncopa@alpinelinux.org>
+pkgname=json-c0.12
+pkgver=0.12.1
+pkgrel=0
+pkgdesc="A JSON implementation in C"
+url="https://github.com/json-c/json-c/wiki"
+arch="all"
+license="MIT"
+makedepends=" autoconf automake libtool"
+subpackages="$pkgname-dev"
+source="https://s3.amazonaws.com/json-c_releases/releases/json-c-${pkgver}.tar.gz
+	"
+
+builddir="$srcdir"/json-c-$pkgver
+prepare() {
+	cd "$builddir"
+	default_prepare
+	autoreconf -f -v -i
+}
+
+build() {
+	cd "$builddir"
+	export CFLAGS="${CFLAGS} -Wno-error=unused-but-set-variable"
+	./configure --prefix=/usr \
+		--build=$CBUILD \
+		--host=$CHOST \
+		--sysconfdir=/etc \
+		--mandir=/usr/share/man \
+		--infodir=/usr/share/info \
+		--localstatedir=/var \
+		--enable-shared \
+		--disable-static \
+		ac_cv_func_malloc_0_nonnull=yes \
+		ac_cv_func_realloc_0_nonnull=yes
+	make -j1
+}
+
+check() {
+	cd "$builddir"
+	make USE_VALGRIND=0 check
+}
+
+package() {
+	cd "$builddir"
+	make -j1 DESTDIR="$pkgdir" install
+}
+
+sha512sums="038676a0ce815e5174161fbd4339524feadc294d517f732fb408ad6aa7c4906423451c13386107569d9f24746a1a101564ca511e92e8276c5bf5b8c022ca42ed  json-c-0.12.1.tar.gz"