dev-qt/qtwebengine: fix build on arm64+clang+musl

Slightly different fix than proposed in bug #981510, but pretty sure
it should work (untested). Please report if there's any issues.

If anyone knows a Gn-only way for chromium to know when it cannot use
this, would be interested -- bonus if upstreamed to chromium itself.

Will add the mte patch in the patchset next time need to update it,
it'll likely be here for a long time. Intentionally excluded from
6.9999 given we skip all chromium-specific patches there, passing
a unused option only results in a warning (albeit it likely won't
build anyway unless chromium fixed this).

The ifunc one is upstreamed, only needed in 6.11.1.

Closes: https://bugs.gentoo.org/981510
Signed-off-by: Ionen Wolkens <ionen@gentoo.org>

dev-qt/qtwebengine/files/qtwebengine-6.11.1-musl-arm64-ifunc.patch

@@ -0,0 +1,12 @@
+https://bugs.gentoo.org/981510
+https://github.com/qt/qtwebengine-chromium/commit/9bfd376e00327
+--- a/src/3rdparty/chromium/base/allocator/partition_allocator/src/partition_alloc/aarch64_support.h
++++ b/src/3rdparty/chromium/base/allocator/partition_allocator/src/partition_alloc/aarch64_support.h
+@@ -16,5 +16,6 @@
+ #include "partition_alloc/buildflags.h"
+ 
+-#if PA_BUILDFLAG(IS_ANDROID) || PA_BUILDFLAG(IS_LINUX)
++#if (PA_BUILDFLAG(IS_ANDROID) || PA_BUILDFLAG(IS_LINUX)) && \
++    __has_include(<sys/ifunc.h>)
+ #define HAS_HW_CAPS
+ #endif

dev-qt/qtwebengine/files/qtwebengine-6.11.1-musl-arm64-mte.patch

@@ -0,0 +1,20 @@
+Add a mean to disable the has_memory_tagging condition so the ebuild
+can disable it where needed. Just a quick solution, ideally Gn itself
+should be able to figure this out.
+
+https://bugs.gentoo.org/981510
+https://gitlab.alpinelinux.org/alpine/aports/-/blob/master/community/chromium/partalloc-no-tagging-arm64.patch
+--- a/src/3rdparty/chromium/base/allocator/partition_allocator/partition_alloc.gni
++++ b/src/3rdparty/chromium/base/allocator/partition_allocator/partition_alloc.gni
+@@ -88,6 +88,10 @@
+ use_large_empty_slot_span_ring = true
+ 
++declare_args() {
++  allow_memory_tagging = true
++}
++
+ has_memory_tagging = current_cpu == "arm64" && is_clang && !is_asan &&
+-                     !is_hwasan && (is_linux || is_android)
++                     !is_hwasan && (is_linux || is_android) && allow_memory_tagging
+ 
+ declare_args() {

dev-qt/qtwebengine/qtwebengine-6.11.1.ebuild

@@ -113,6 +113,8 @@ PATCHES+=(
 	"${FILESDIR}"/${PN}-6.11.0-gcc17.patch
 	"${FILESDIR}"/${PN}-6.11.1-gcc17.patch
 	"${FILESDIR}"/${PN}-6.11.1-musl-missing-includes.patch
+	"${FILESDIR}"/${PN}-6.11.1-musl-arm64-ifunc.patch
+	"${FILESDIR}"/${PN}-6.11.1-musl-arm64-mte.patch
 )
 
 python_check_deps() {
@@ -244,6 +246,9 @@ src_configure() {
 		symbol_level=0
 	)
 
+	use arm64 && use elibc_musl &&
+		mygnargs+=( allow_memory_tagging=false ) #981510
+
 	if use !custom-cflags; then
 		# qtwebengine can be rather fragile with *FLAGS
 		filter-lto

dev-qt/qtwebengine/qtwebengine-6.11.2.ebuild

@@ -112,6 +112,7 @@ PATCHES+=(
 	"${FILESDIR}"/${PN}-6.10.3-climits.patch
 	"${FILESDIR}"/${PN}-6.11.0-gcc17.patch
 	"${FILESDIR}"/${PN}-6.11.1-musl-missing-includes.patch
+	"${FILESDIR}"/${PN}-6.11.1-musl-arm64-mte.patch
 )
 
 python_check_deps() {
@@ -243,6 +244,9 @@ src_configure() {
 		symbol_level=0
 	)
 
+	use arm64 && use elibc_musl &&
+		mygnargs+=( allow_memory_tagging=false ) #981510
+
 	if use !custom-cflags; then
 		# qtwebengine can be rather fragile with *FLAGS
 		filter-lto

dev-qt/qtwebengine/qtwebengine-6.11.9999.ebuild

@@ -112,6 +112,7 @@ PATCHES+=(
 	"${FILESDIR}"/${PN}-6.10.3-climits.patch
 	"${FILESDIR}"/${PN}-6.11.0-gcc17.patch
 	"${FILESDIR}"/${PN}-6.11.1-musl-missing-includes.patch
+	"${FILESDIR}"/${PN}-6.11.1-musl-arm64-mte.patch
 )
 
 python_check_deps() {
@@ -243,6 +244,9 @@ src_configure() {
 		symbol_level=0
 	)
 
+	use arm64 && use elibc_musl &&
+		mygnargs+=( allow_memory_tagging=false ) #981510
+
 	if use !custom-cflags; then
 		# qtwebengine can be rather fragile with *FLAGS
 		filter-lto

dev-qt/qtwebengine/qtwebengine-6.12.9999.ebuild

@@ -112,6 +112,7 @@ PATCHES+=(
 	"${FILESDIR}"/${PN}-6.10.3-climits.patch
 	"${FILESDIR}"/${PN}-6.11.0-gcc17.patch
 	"${FILESDIR}"/${PN}-6.11.1-musl-missing-includes.patch
+	"${FILESDIR}"/${PN}-6.11.1-musl-arm64-mte.patch
 )
 
 python_check_deps() {
@@ -243,6 +244,9 @@ src_configure() {
 		symbol_level=0
 	)
 
+	use arm64 && use elibc_musl &&
+		mygnargs+=( allow_memory_tagging=false ) #981510
+
 	if use !custom-cflags; then
 		# qtwebengine can be rather fragile with *FLAGS
 		filter-lto

dev-qt/qtwebengine/qtwebengine-6.9999.ebuild

@@ -242,6 +242,9 @@ src_configure() {
 		symbol_level=0
 	)
 
+	use arm64 && use elibc_musl &&
+		mygnargs+=( allow_memory_tagging=false ) #981510
+
 	if use !custom-cflags; then
 		# qtwebengine can be rather fragile with *FLAGS
 		filter-lto