diff --git a/debian/changelog b/debian/changelog
index 0e13d098..663a6dac 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,5 +1,6 @@
 llvm-toolchain-15 (1:15.0.7-2) UNRELEASED; urgency=medium
 
+  [ Sylvestre Ledru ]
   * Adjust some lintian overrides
   * Disable flang on s390x. Seems that it is breaking
 
@@ -13,6 +14,12 @@ llvm-toolchain-15 (1:15.0.7-2) UNRELEASED; urgency=medium
   [ John Paul Adrian Glaubitz ]
   * Don't run chrpath for libclang on powerpc and powerpcspe
 
+  [ Faidon Liambotis ]
+  * Update the wasm-sysroot-usr.diff patch to restore functionality that was
+    accidentally dropped when the patch was forward-ported from 14 to 15. This
+    resolves an issue in which clang++ builds would fail if libc++-15-dev was
+    installed alongside libc++-15-dev-wasm32. (Closes: #1029010, #1032317)
+
  -- Sylvestre Ledru <sylvestre@debian.org>  Sun, 15 Jan 2023 10:54:41 +0100
 
 llvm-toolchain-15 (1:15.0.7-1) unstable; urgency=medium
diff --git a/debian/patches/wasm/wasm-sysroot-usr.diff b/debian/patches/wasm/wasm-sysroot-usr.diff
index e3270aa2..6587c1bd 100644
--- a/debian/patches/wasm/wasm-sysroot-usr.diff
+++ b/debian/patches/wasm/wasm-sysroot-usr.diff
@@ -57,6 +57,33 @@
  void WebAssembly::addLibCxxIncludePaths(
      const llvm::opt::ArgList &DriverArgs,
      llvm::opt::ArgStringList &CC1Args) const {
+@@ -499,7 +519,9 @@ void WebAssembly::addLibCxxIncludePaths(
+   }
+ 
+   // Second add the generic one.
+-  addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version);
++  // don't include the host architecture's headers in the search path
++  if (!getDriver().SysRoot.empty())
++    addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version);
+ }
+ 
+ void WebAssembly::addLibStdCXXIncludePaths(
+@@ -546,8 +568,11 @@ void WebAssembly::addLibStdCXXIncludePat
+     addSystemInclude(DriverArgs, CC1Args, TargetDir);
+   }
+ 
+-  // Second add the generic one.
+-  addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version);
+-  // Third the backward one.
+-  addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version + "/backward");
++  // don't include the host architecture's headers in the search path
++  if (!getDriver().SysRoot.empty()) {
++    // Second add the generic one.
++    addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version);
++    // Third the backward one.
++    addSystemInclude(DriverArgs, CC1Args, LibPath + "/c++/" + Version + "/backward");
++  }
+ }
 --- a/clang/lib/Driver/ToolChains/WebAssembly.h
 +++ b/clang/lib/Driver/ToolChains/WebAssembly.h
 @@ -89,6 +89,8 @@ private: