[CMAKE] Disable a number of warnings for clang

Also remove the totally useless and stupid -Werror=unknown-warning-option

sdk/cmake/gcc.cmake

@@ -115,22 +115,22 @@ add_compile_options(-march=${OARCH} -mtune=${TUNE})
 # Warnings, errors
 if((NOT CMAKE_BUILD_TYPE STREQUAL "Release") AND (NOT CMAKE_C_COMPILER_ID STREQUAL Clang))
     add_compile_options(-Werror)
-else()
-    if(CMAKE_C_COMPILER_ID STREQUAL "Clang")
-        add_compile_options($<$<COMPILE_LANGUAGE:C,CXX>:-Werror=unknown-warning-option>)
-    endif()
 endif()
 
 add_compile_options(-Wall -Wpointer-arith)
-add_compile_options(-Wno-char-subscripts -Wno-multichar -Wno-unused-value)
-add_compile_options(-Wno-unused-const-variable)
-add_compile_options(-Wno-unused-local-typedefs)
-add_compile_options(-Wno-deprecated)
-add_compile_options(-Wno-unused-result) # FIXME To be removed when CORE-17637 is resolved
 
-if(NOT CMAKE_C_COMPILER_ID STREQUAL "Clang")
-    add_compile_options(-Wno-maybe-uninitialized)
-endif()
+# Disable some overzealous warnings
+add_compile_options(
+    -Wno-unknown-warning-option
+    -Wno-char-subscripts
+    -Wno-multichar
+    -Wno-unused-value
+    -Wno-unused-const-variable
+    -Wno-unused-local-typedefs
+    -Wno-deprecated
+    -Wno-unused-result # FIXME To be removed when CORE-17637 is resolved
+    -Wno-maybe-uninitialized
+)
 
 if(ARCH STREQUAL "amd64")
     add_compile_options(-Wno-format)

sdk/cmake/msvc.cmake

@@ -147,8 +147,20 @@ endif()
 add_compile_options(/w14115)
 
 if(CMAKE_C_COMPILER_ID STREQUAL "Clang")
-    add_compile_options($<$<COMPILE_LANGUAGE:C,CXX>:-Werror=unknown-warning-option>)
-    add_compile_options("$<$<COMPILE_LANGUAGE:C,CXX>:-nostdinc;-Wno-multichar;-Wno-char-subscripts;-Wno-microsoft-enum-forward-reference;-Wno-pragma-pack;-Wno-microsoft-anon-tag;-Wno-parentheses-equality;-Wno-unknown-pragmas>")
+    add_compile_options("$<$<COMPILE_LANGUAGE:C,CXX>:-nostdinc>")
+    add_compile_options(
+        -Wno-unknown-warning-option
+        -Wno-multichar
+        -Wno-char-subscripts
+        -Wno-microsoft-enum-forward-reference
+        -Wno-pragma-pack
+        -Wno-microsoft-anon-tag
+        -Wno-parentheses-equality
+        -Wno-unknown-pragmas
+        -Wno-ignored-pragmas
+        -Wno-ignored-pragma-intrinsic
+        -Wno-microsoft-exception-spec
+    )
 endif()
 
 # Debugging