sci-libs/primegen: Fix build error and update EAPI 7 -> 8

type specifier missing, defaults to int

Closes: https://bugs.gentoo.org/898288
Signed-off-by: Brahmajit Das <brahmajit.xyz@gmail.com>
Closes: https://github.com/gentoo/gentoo/pull/31464
Signed-off-by: Andrew Ammerlaan <andrewammerlaan@gentoo.org>

sci-libs/primegen/files/primegen-0.97-main-rettype.patch

@@ -0,0 +1,13 @@
+Adding return type to main function
+Bug: https://bugs.gentoo.org/898288
+--- a/eratspeed.c
++++ b/eratspeed.c
+@@ -402,7 +402,7 @@ void countit()
+ timing t;
+ timing told;
+ 
+-main()
++int main()
+ {
+   int L = 1;
+ 

sci-libs/primegen/primegen-0.97-r3.ebuild

@@ -0,0 +1,58 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit flag-o-matic toolchain-funcs
+
+DESCRIPTION="Small, fast library to generate primes in order"
+HOMEPAGE="https://cr.yp.to/primegen.html"
+SRC_URI="https://cr.yp.to/primegen/${P}.tar.gz"
+
+LICENSE="public-domain"
+SLOT="0"
+KEYWORDS="~amd64 ~ppc ~x86 ~amd64-linux ~x86-linux"
+
+PATCHES=(
+	"${FILESDIR}"/${P}-man.patch
+	"${FILESDIR}"/${P}-missing-headers.patch
+	"${FILESDIR}"/${P}-respect-ar-ranlib.patch
+	"${FILESDIR}"/${PN}-0.97-main-rettype.patch
+)
+
+src_prepare() {
+	default
+
+	local file
+	while IFS="" read -d $'\0' -r file; do
+		sed -i -e 's:\(primegen.a\):lib\1:' "${file}" || die
+	done < <(find . -type f -print0)
+	mkdir usr || die
+}
+
+src_configure() {
+	# Fixes bug #161015
+	append-flags -fsigned-char
+	echo "$(tc-getCC) ${CFLAGS} ${CPPFLAGS}" > conf-cc || die
+	echo "${S}/usr" > conf-home || die
+	echo "$(tc-getCC) ${LDFLAGS}" > conf-ld || die
+	tc-export AR RANLIB
+}
+
+src_test() {
+	[[ $(./primes 1 100000000 | md5sum ) == "4e2b0027288a27e9c99699364877c9db "* ]] || die "test failed"
+}
+
+src_install() {
+	dobin primegaps primes primespeed
+	doman primegaps.1 primes.1 primespeed.1 primegen.3
+	dolib.a libprimegen.a
+	# include the 2 typedefs to avoid collision (bug #248327)
+	sed -i \
+		-e "s/#include \"uint32.h\"/$(grep typedef uint32.h)/" \
+		-e "s/#include \"uint64.h\"/$(grep typedef uint64.h)/" \
+		primegen.h || die
+
+	doheader primegen.h
+	dodoc BLURB CHANGES README TODO
+}