sys-boot/silo: fix build failure against gcc-6, bug #639224

It's a commit similar to d534bffc05
("sys-boot/aboot: fix link failure on recent gcc (force gnu90)")

c99 and gnu90 have slightly different semantics
WRT symbol definition: http://www.greenend.org.uk/rjk/tech/inline.html

Reported-by: Rolf Eike Beer
Closes: https://bugs.gentoo.org/639224
Package-Manager: Portage-2.3.19, Repoman-2.3.6

sys-boot/silo/files/silo-1.4.14_p20120819-gnu90-inline.patch

@@ -0,0 +1,20 @@
+--- a/Rules.make
++++ b/Rules.make
+@@ -26,2 +26,7 @@ CFLAGS += -fno-stack-protector
+ endif
++ifeq ($(call cc-option-yn, -std=gnu90),y)
++# In gcc-5+ c99 changed inline rules by forbidding
++# multiple extern definitions. Fall back to gnu90
++CFLAGS += -std=gnu90
++endif
+ 
+--- a/silo/Makefile
++++ b/silo/Makefile
+@@ -6,2 +6,7 @@ UFSDEPS=
+ CFLAGS=-O2 -Wall -I. -I../include
++ifeq ($(call cc-option-yn, -std=gnu90),y)
++# In gcc-5+ c99 changed inline rules by forbidding
++# multiple extern definitions. Fall back to gnu90
++CFLAGS += -std=gnu90
++endif
+ 

sys-boot/silo/silo-1.4.14_p20120819-r1.ebuild

@@ -0,0 +1,69 @@
+# Copyright 1999-2018 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=6
+
+inherit mount-boot flag-o-matic toolchain-funcs eutils
+
+DEB_PL="1"
+MY_PV="${PV##*_p}"
+MY_GIT="git${MY_PV%%_*}"
+MY_PV="${PV%%_*}"
+MY_P="${PN}_${MY_PV}+${MY_GIT}"
+
+DESCRIPTION="SPARC/UltraSPARC Improved Loader, a boot loader for sparc"
+SRC_URI="mirror://debian/pool/main/s/${PN}/${MY_P}.orig.tar.gz
+	mirror://debian/pool/main/s/${PN}/${MY_P}-${DEB_PL}.diff.gz"
+HOMEPAGE="https://git.kernel.org/?p=linux/kernel/git/davem/silo.git;a=summary"
+
+SLOT="0"
+LICENSE="GPL-2"
+KEYWORDS="-* ~sparc"
+IUSE=""
+
+DEPEND="sys-fs/e2fsprogs
+	sys-apps/sparc-utils"
+RDEPEND=""
+
+ABI_ALLOW="sparc32"
+
+S="${WORKDIR}/${PN}"
+
+PATCHES=(
+	"${FILESDIR}"/${P}-gnu90-inline.patch
+)
+
+src_prepare() {
+	default
+
+	#Set the correct version
+	sed -i -e "s/1.4.14/1.4.14_git20120819_p1/g" Rules.make || die
+
+	# Fix build failure
+	sed -i -e "s/-fno-strict-aliasing/-fno-strict-aliasing -U_FORTIFY_SOURCE -mcpu=v9/g" Rules.make || die
+}
+
+src_compile() {
+	filter-flags "-fstack-protector"
+
+	emake CC="$(tc-getCC)"
+}
+
+src_install() {
+	default
+
+	dodoc first-isofs/README.SILO_ISOFS docs/README*
+
+	# Fix maketilo manpage
+	rm "${D}"/usr/share/man/man1/maketilo.1
+	dosym tilo.1 /usr/share/man/man1/maketilo.1
+}
+
+pkg_postinst() {
+	mount-boot_pkg_postinst
+	ewarn "NOTE: If this is an upgrade to an existing SILO install,"
+	ewarn "      you will need to re-run silo as the /boot/second.b"
+	ewarn "      file has changed, else the system will fail to load"
+	ewarn "      SILO at the next boot."
+	ewarn
+}