main/gcc: add bugurl

this makes the bug info at the bottom of --help (and segfaults?):

For bug reporting instructions, please see:
<https://gitlab.alpinelinux.org/alpine/aports/-/issues>.

which is where all issues should go, especially for this gcc given the
large patchset.

main/gcc/APKBUILD

@@ -9,7 +9,7 @@ pkgver=12.1.1_git20220630
 [ "$CHOST" != "$CTARGET" ] && _target="-$CTARGET_ARCH" || _target=""
 
 pkgname="$pkgname$_target"
-pkgrel=3
+pkgrel=4
 pkgdesc="The GNU Compiler Collection"
 url="https://gcc.gnu.org"
 arch="all"
@@ -374,6 +374,7 @@ build() {
 		$_cross_configure \
 		$_bootstrap_configure \
 		$_jit_configure \
+		--with-bugurl="https://gitlab.alpinelinux.org/alpine/aports/-/issues" \
 		--with-system-zlib \
 		$_hash_style_configure
 	make