dev-debug/valgrind: fix build w/ gcc-16

Signed-off-by: Sam James <sam@gentoo.org>

dev-debug/valgrind/files/valgrind-3.26.0-gcc16.patch

@@ -0,0 +1,21 @@
+Small backport(ish) of https://sourceware.org/git/?p=valgrind.git;a=commit;h=51c5973d9d1f096b9472df75638f2a53324fafed
+--- a/configure.ac
++++ b/configure.ac
+@@ -2591,7 +2591,7 @@ AC_GCC_WARNING_SUBST_NO([unused-result], [FLAG_W_NO_UNUSED_RESULT])
+ AC_GCC_WARNING_SUBST_NO([infinite-recursion], [FLAG_W_NO_INFINITE_RECURSION])
+ AC_GCC_WARNING_SUBST_NO([deprecated], [FLAG_W_NO_DEPRECATED])
+ # OK for 32 and 64 bit
+-AC_GCC_WARNING_SUBST_NO([alloc-size-larger-than=18446744073709551615], [FLAG_W_NO_ALLOC_SIZE_LARGER_THAN])
++AC_GCC_WARNING_SUBST([alloc-size-larger-than=18446744073709551616], [FLAG_W_NO_ALLOC_SIZE_LARGER_THAN])
+ AC_GCC_WARNING_SUBST_NO([alloc-size], [FLAG_W_NO_ALLOC_SIZE])
+ 
+ AC_GCC_WARNING_SUBST([write-strings], [FLAG_W_WRITE_STRINGS])
+@@ -2610,7 +2610,7 @@ AC_GCC_WARNING_SUBST([implicit-fallthrough=2], [FLAG_W_IMPLICIT_FALLTHROUGH])
+ AC_DEFUN([AC_GXX_WARNING_SUBST_NO],[
+   AC_MSG_CHECKING([if g++ accepts -W$1])
+   safe_CXXFLAGS=$CXXFLAGS
+-  CXXFLAGS="-W$1 -Werror"
++  CXXFLAGS="-W$1 -Wno-$1 -Werror"
+   AC_LANG_PUSH(C++)
+   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[;]])], [
+                     AC_SUBST([$2], [-Wno-$1])

dev-debug/valgrind/valgrind-3.26.0.ebuild

@@ -67,6 +67,7 @@ PATCHES=(
 	"${FILESDIR}"/${PN}-3.7.0-respect-flags.patch
 	"${FILESDIR}"/${PN}-3.15.0-Build-ldst_multiple-test-with-fno-pie.patch
 	"${FILESDIR}"/${PN}-3.21.0-glibc-2.34-suppressions.patch
+	"${FILESDIR}"/${P}-gcc16.patch
 )
 
 QA_CONFIG_IMPL_DECL_SKIP+=(