diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5c99bdd9a0..764046a240 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -315,9 +315,10 @@ endif()
 
 # For Visual Studio prior to 2022 (compiler < 19.30) /fp:strict
 # For Visual Studio 2022 (compiler >= 19.30) /fp:precise
-# For Visual Studio 2022 ClangCL seems to have accidentally enabled contraction by default,
-# so behaves differently to CL.exe. Use the -Xclang argument to workaround and allow access
-# GNU-style switch to control contraction and force disable.
+# For Visual Studio 2022 ClangCL has enabled contraction by default,
+# which is the same as standard clang, so behaves differently to
+# CL.exe. Use the -Xclang argument to access GNU-style switch to
+# control contraction and force disable.
 
 # On CMake 3.25 or older CXX_COMPILER_FRONTEND_VARIANT is not always set
 if(CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "")
@@ -338,6 +339,7 @@ set(is_gnu_fe1 "$<STREQUAL:${CMAKE_CXX_COMPILER_FRONTEND_VARIANT},GNU>")
 set(is_gnu_fe2 "$<STREQUAL:${CMAKE_CXX_COMPILER_FRONTEND_VARIANT},AppleClang>")
 # Compiler accepts GNU-style command line options
 set(is_gnu_fe "$<OR:${is_gnu_fe1},${is_gnu_fe2}>")
+#add_custom_target(debug_isgnufe1 COMMAND ${CMAKE_COMMAND} -E echo "is_gnufe1_exp = $<STREQUAL:${CMAKE_CXX_COMPILER_FRONTEND_VARIANT},GNU>")
 
 # Compiler is Visual Studio cl.exe
 set(is_msvccl "$<AND:${is_msvc_fe},$<CXX_COMPILER_ID:MSVC>>")
@@ -346,24 +348,18 @@ set(is_clangcl "$<AND:${is_msvc_fe},$<CXX_COMPILER_ID:Clang>>")
 # Compiler is upstream clang with the standard frontend
 set(is_clang "$<AND:${is_gnu_fe},$<CXX_COMPILER_ID:Clang,AppleClang>>")
 
-if(${is_msvccl} AND $<VERSION_LESS:$<CXX_COMPILER_VERSION>,19.30>)
-    add_compile_options(/fp:strict)
-endif()
-if(${is_msvccl} AND $<VERSION_GREATER_EQUAL:$<CXX_COMPILER_VERSION>,19.30>)
-    add_compile_options(/fp:precise)
-endif()
-if(${is_clangcl})
-    add_compile_options(/fp:precise)
-endif()
-if(${is_clangcl} AND $<VERSION_GREATER_EQUAL:$<CXX_COMPILER_VERSION>,14.0.0>)
-    add_compile_options(-Xclang -ffp-contract=off)
-endif()
-if(${is_clang} AND $<VERSION_GREATER_EQUAL:$<CXX_COMPILER_VERSION>,10.0.0>)
-    add_compile_options(-ffp-model=precise)
-endif()
-if(${is_gnu_fe})
-    add_compile_options(-ffp-contract=off)
-endif()
+add_compile_options(
+    $<$<AND:${is_msvccl},$<VERSION_LESS:$<CXX_COMPILER_VERSION>,19.30>>:/fp:strict>
+    $<$<AND:${is_msvccl},$<VERSION_GREATER_EQUAL:$<CXX_COMPILER_VERSION>,19.30>>:/fp:precise>
+    $<${is_clangcl}:/fp:precise>
+    $<$<AND:${is_clangcl},$<VERSION_GREATER_EQUAL:$<CXX_COMPILER_VERSION>,14.0.0>>:-Xclang$<SEMICOLON>-ffp-contract=off>
+    $<$<AND:${is_clang},$<VERSION_GREATER_EQUAL:$<CXX_COMPILER_VERSION>,10.0.0>>:-ffp-model=precise>
+    $<${is_gnu_fe}:-ffp-contract=off>
+    # Hide noise from clang and clangcl 20 warning the 2nd fp option changes
+    # one of the settings made the first.
+    $<$<AND:${is_clang},$<VERSION_GREATER_EQUAL:$<CXX_COMPILER_VERSION>,20.0.0>>:-Wno-overriding-option>
+)
+#add_custom_target(debug_gnufe_ffpcontract COMMAND ${CMAKE_COMMAND} -E echo "ffp_contract = $<${is_gnu_fe}:-ffp-contract=off>")
 
 set(KTX_BUILD_DIR "${CMAKE_BINARY_DIR}")
 
diff --git a/external/astc-encoder/Source/cmake_core.cmake b/external/astc-encoder/Source/cmake_core.cmake
index e78eb70bba..be43ee913b 100644
--- a/external/astc-encoder/Source/cmake_core.cmake
+++ b/external/astc-encoder/Source/cmake_core.cmake
@@ -176,6 +176,7 @@ macro(astcenc_set_properties ASTCENC_TARGET_NAME ASTCENC_IS_VENEER)
             $<${is_gnu_fe}:-Wno-float-equal>
             $<${is_gnu_fe}:-Wno-deprecated-declarations>
             $<${is_gnu_fe}:-Wno-atomic-implicit-seq-cst>
+            $<${is_clang}:-Wno-overriding-option>
 
             # Clang 10 also throws up warnings we need to investigate (ours)
             $<${is_gnu_fe}:-Wno-cast-align>
diff --git a/scripts/build_wasm_docker.sh b/scripts/build_wasm_docker.sh
index 0d15396dbf..9e80ed0540 100755
--- a/scripts/build_wasm_docker.sh
+++ b/scripts/build_wasm_docker.sh
@@ -74,12 +74,18 @@ mkdir -p $BUILD_DIR
 # emcmake uses the "Unix Makefiles" generator on Linux which does not
 # support multiple configurations.
 echo "Configure and Build KTX-Software (Web $CONFIGURATION)"
+
+# Uncomment and set to desired targets if you don't want to build everything.
+#targets="--target debug_isgnufe1 --target debug_gnufe_ffpcontract"
+# Uncomment to have make run in verbose mode.
+#verbose_make="-- VERBOSE=1"
+
 docker exec -it emscripten sh -c "emcmake cmake -B$BUILD_DIR . \
     -D CMAKE_BUILD_TYPE=$CONFIGURATION \
     -D KTX_FEATURE_DOC=OFF \
     -D KTX_FEATURE_LOADTEST_APPS=$FEATURE_LOADTESTS \
     -D KTX_WERROR=$WERROR \
-  && cmake --build $BUILD_DIR"
+  && cmake --build $BUILD_DIR $targets $verbose_make"
 
 if [ "$PACKAGE" = "YES" ]; then
   echo "Pack KTX-Software (Web $CONFIGURATION)"