dev-util/ccache: fix build of bundled libfmt on libc++ 21

Signed-off-by: Violet Purcell <vimproved@inventati.org>
Part-of: https://github.com/gentoo/gentoo/pull/43171
Signed-off-by: Sam James <sam@gentoo.org>

dev-util/ccache/ccache-4.11.3.ebuild

@@ -75,6 +75,7 @@ PATCHES=(
 	"${FILESDIR}"/${PN}-3.5-nvcc-test.patch
 	"${FILESDIR}"/${PN}-4.0-objdump.patch
 	"${FILESDIR}"/${PN}-4.11-avoid-run-user.patch
+	"${FILESDIR}"/${PN}-4.11.3-libfmt-libcxx-21.patch
 )
 
 src_unpack() {

dev-util/ccache/files/ccache-4.11.3-libfmt-libcxx-21.patch

@@ -0,0 +1,37 @@
+From https://github.com/fmtlib/fmt/commit/f4345467fce7edbc6b36c3fa1cf197a67be617e2 Mon Sep 17 00:00:00 2001
+From: Remy Jette <remy@remyjette.com>
+Date: Sat, 21 Jun 2025 07:28:14 -0700
+Subject: [PATCH] Fix compilation on clang-21 / libc++-21 (#4477)
+
+`<cstdlib>` was not being included, so malloc and free were only declared
+via transitive includes. Some includes changed in the latest libc++-21
+build which broke fmt.
+
+Also changed `malloc`/`free` to `std::malloc` and `std::free`, as
+putting those symbols in the global namespace is optional for the
+implementation when including `<cstdlib>`.
+--- a/src/third_party/fmt/fmt/format.h
++++ b/src/third_party/fmt/fmt/format.h
+@@ -44,6 +44,7 @@
+ #  include <cmath>    // std::signbit
+ #  include <cstddef>  // std::byte
+ #  include <cstdint>  // uint32_t
++#  include <cstdlib>  // std::malloc, std::free
+ #  include <cstring>  // std::memcpy
+ #  include <limits>   // std::numeric_limits
+ #  include <new>      // std::bad_alloc
+@@ -755,12 +756,12 @@ template <typename T> struct allocator : private std::decay<void> {
+ 
+   T* allocate(size_t n) {
+     FMT_ASSERT(n <= max_value<size_t>() / sizeof(T), "");
+-    T* p = static_cast<T*>(malloc(n * sizeof(T)));
++    T* p = static_cast<T*>(std::malloc(n * sizeof(T)));
+     if (!p) FMT_THROW(std::bad_alloc());
+     return p;
+   }
+ 
+-  void deallocate(T* p, size_t) { free(p); }
++  void deallocate(T* p, size_t) { std::free(p); }
+ };
+ 
+ }  // namespace detail