diff --git a/pkgs/development/web/playwright/webkit.nix b/pkgs/development/web/playwright/webkit.nix
index a068c052825f..1254070e6f6f 100644
--- a/pkgs/development/web/playwright/webkit.nix
+++ b/pkgs/development/web/playwright/webkit.nix
@@ -106,6 +106,14 @@ let
         # Fix multiple definition errors by using C++17 instead of C++11
         substituteInPlace CMakeLists.txt \
           --replace "set(CMAKE_CXX_STANDARD 11)" "set(CMAKE_CXX_STANDARD 17)"
+        # Fix the build with CMake 4.
+        # See:
+        # * <https://github.com/webmproject/sjpeg/commit/9990bdceb22612a62f1492462ef7423f48154072>
+        # * <https://github.com/webmproject/sjpeg/commit/94e0df6d0f8b44228de5be0ff35efb9f946a13c9>
+        substituteInPlace third_party/sjpeg/CMakeLists.txt \
+          --replace-fail \
+            'cmake_minimum_required(VERSION 2.8.7)' \
+            'cmake_minimum_required(VERSION 3.5...3.10)'
       '';
       postInstall = "";
 
diff --git a/pkgs/tools/text/diffutils/default.nix b/pkgs/tools/text/diffutils/default.nix
index 916dc2255576..d82686d98c3e 100644
--- a/pkgs/tools/text/diffutils/default.nix
+++ b/pkgs/tools/text/diffutils/default.nix
@@ -31,6 +31,9 @@ stdenv.mkDerivation rec {
     # https://lists.gnu.org/archive/html/bug-gnulib/2025-07/msg00021.html
     # Multiple upstream commits squashed with adjustments, see header
     ./gnulib-float-h-tests-port-to-C23-PowerPC-GCC.patch
+  ]
+  ++ lib.optionals stdenv.hostPlatform.useLLVM [
+    ./musl-llvm.patch
   ];
 
   nativeBuildInputs = [
diff --git a/pkgs/tools/text/diffutils/musl-llvm.patch b/pkgs/tools/text/diffutils/musl-llvm.patch
new file mode 100644
index 000000000000..535a64d1ab79
--- /dev/null
+++ b/pkgs/tools/text/diffutils/musl-llvm.patch
@@ -0,0 +1,15 @@
+---
+ gnulib-tests/test-c32ispunct.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/gnulib-tests/test-c32ispunct.c
++++ b/gnulib-tests/test-c32ispunct.c
+@@ -255,7 +255,7 @@ main (int argc, char *argv[])
+           is = for_character ("\360\235\204\200", 4);
+           ASSERT (is != 0);
+         #endif
+-        #if !(defined __GLIBC__ || (defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ || defined _AIX || defined __sun || defined __CYGWIN__ || (defined _WIN32 && !defined __CYGWIN__) || defined __ANDROID__)
++        #if !(defined __GLIBC__ || defined MUSL_LIBC || (defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ || defined _AIX || defined __sun || defined __CYGWIN__ || (defined _WIN32 && !defined __CYGWIN__) || defined __ANDROID__)
+           /* U+E003A TAG COLON */
+           is = for_character ("\363\240\200\272", 4);
+           ASSERT (is == 0);