gummiboot: fix build failure

Closes #10867.

Signed-off-by: Enno Boland <gottox@voidlinux.eu>

srcpkgs/gummiboot/template

@@ -1,7 +1,7 @@
 # Template file for 'gummiboot'
 pkgname=gummiboot
 version=48
-revision=2
+revision=3
 build_style=gnu-configure
 hostmakedepends="automake pkg-config libxslt docbook-xsl"
 makedepends="gnu-efi-libs liblzma-devel libblkid-devel"
@@ -13,6 +13,8 @@ distfiles="http://cgit.freedesktop.org/${pkgname}/snapshot/${pkgname}-${version}
 checksum=ea228571d962be6a06a64291e507e9cfe4ef0f46acfacc0677f211d1ced458d6
 only_for_archs="i686 i686-musl x86_64 x86_64-musl"
 
+CFLAGS="-std=gnu89"
+
 configure_args="--with-efi-ldsdir=${XBPS_CROSS_BASE}/usr/lib
 		--with-efi-libdir=${XBPS_CROSS_BASE}/usr/lib
 		--with-efi-includedir=${XBPS_CROSS_BASE}/usr/include"
@@ -21,6 +23,10 @@ pre_configure() {
 	./autogen.sh
 }
 
+pre_build() {
+	sed -i Makefile -e "s/\-nostdinc//g"
+}
+
 post_install() {
 	vinstall ${FILESDIR}/kernel.d/gummiboot.post-install 750 \
 		etc/kernel.d/post-install 50-gummiboot