diff --git a/.clangd b/.clangd
new file mode 100644
index 00000000..c654ac92
--- /dev/null
+++ b/.clangd
@@ -0,0 +1,2 @@
+CompileFlags:
+  Add: [-D__CLANGD__]
diff --git a/include/decomp.h b/include/decomp.h
index 3ad73a47..e0511da1 100644
--- a/include/decomp.h
+++ b/include/decomp.h
@@ -25,7 +25,8 @@ typedef struct ps_f32 {
   SECTION_GARBAGE static void __garbage_ordering_hints(void)
 #define order_hint_access(var) (void)(var)
 
-#elif defined (__INTELLISENSE__)
+#elif defined (__EDITOR_CHECKING__)
+// dummy implementations for editor tooling
 
 #define sdata_ps_f32 ps_f32
 #define sdata2_ps_f32 ps_f32
@@ -35,9 +36,7 @@ typedef struct ps_f32 {
 #define SECTION_GARBAGE
 #define static_order_hints
 #define order_hint_access(var) (void)(var)
-
-#endif
-
-#ifdef __clang__
-#define __cntlzw(x) __builtin_clz(x)
+// TODO(KooShnoo): is builtin preferred?
+#define __cntlzw(x) (x)
+// #define __cntlzw(x) __builtin_clz(x)
 #endif
diff --git a/include/macros.h b/include/macros.h
index 083688c5..829bd902 100644
--- a/include/macros.h
+++ b/include/macros.h
@@ -24,16 +24,21 @@
 
 #define DECLTYPE(x) __decltype__(x)
 
-// https://github.com/DarkRTA/rb3/blob/235050f88a263fec0387b7c618dda76a8bb24d2c/src/sdk/RVL_SDK/revolution/os/OSUtils.h#L13-L17
-#if defined(__CWCC__) && !defined(__INTELLISENSE__)
-#define AT_ADDRESS(addr) : (addr)
-#else
-#define AT_ADDRESS(addr)
+#if defined(__INTELLISENSE__) || defined(__CLANGD__)
+// TODO(KooShnoo): are we happy with this name?
+#define __EDITOR_CHECKING__
 #endif
 
-// For VSCode
-#ifdef __INTELLISENSE__
+#ifdef __CWCC__
+// codewarrior-specific syntax
+#define AT_ADDRESS(addr) : (addr)
+#elif defined(__EDITOR_CHECKING__)
+// dummy implementations for editor tooling
+#define AT_ADDRESS(addr)
 #define asm
 #define __attribute__(x)
 #define __declspec(x)
+#else
+// building with a non-codewarrior compiler is not supported yet
+#error "workarounds for codewarrior's language extensions unimplemented"
 #endif
diff --git a/include/rk_types.h b/include/rk_types.h
index 0a9b36b2..6185ea2d 100644
--- a/include/rk_types.h
+++ b/include/rk_types.h
@@ -111,7 +111,7 @@ class NonCopyable {
 
 
 // Main static assert macro
-#if defined(__INTELLISENSE__)
+#ifdef __EDITOR_CHECKING__
   #if !__has_extension(c_static_assert)
     #error "language server lacks `_Static_assert` support"
   #endif
diff --git a/lib/MSL/include/math.h b/lib/MSL/include/math.h
index 9b7a51f6..ee393646 100644
--- a/lib/MSL/include/math.h
+++ b/lib/MSL/include/math.h
@@ -25,9 +25,12 @@ inline f32 sqrtf(f32 x) { return (f32)sqrt(x); }
 f64 acos(f64);
 inline f32 acosf(f32 x) { return (f32)acos(x); }
 
-#ifdef __INTELLISENSE__
-#define __fabsf(x) x
-#define __fabs(x) x
+#ifdef __CWCC__
+// when using the codewarrior compiler, __fabs and __fabsf are builtin intrinsics.
+#elif defined(__EDITOR_CHECKING__)
+// dummy implementation for editor tooling
+#define __fabsf(x) (x)
+#define __fabs(x) (x)
 #endif
 
 f32 fabsf(f32);
diff --git a/lib/MSL/include/stddef.h b/lib/MSL/include/stddef.h
index a719e004..810d1e29 100644
--- a/lib/MSL/include/stddef.h
+++ b/lib/MSL/include/stddef.h
@@ -1,6 +1,8 @@
 #pragma once
 
-#ifdef __INTELLISENSE__
+#include "macros.h"
+
+#ifdef __EDITOR_CHECKING__
 #define offsetof(type, m) __builtin_offsetof(type,m)
 #else
 #define offsetof(type, m) ((size_t) & (((type*)0)->m))
diff --git a/lib/MSL/include/stdlib.h b/lib/MSL/include/stdlib.h
index 41697608..8848bef7 100644
--- a/lib/MSL/include/stdlib.h
+++ b/lib/MSL/include/stdlib.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include "macros.h"
+
 #ifndef SIZE_T_DEFINE
 #define SIZE_T_DEFINE
 typedef unsigned long size_t;
@@ -9,11 +11,10 @@ typedef unsigned long size_t;
 #ifdef __CWCC__
 #define abs(x) __abs(x)
 #define labs(x) __labs(x)
-#elif defined(__clang__)
-#define abs(x) __builtin_abs(x)
-#define labs(x) __builtin_labs(x)
-#else
-#error compiler has no instrinsic abs support, please do some sit ups.
+#elif defined(__EDITOR_CHECKING__)
+// dummy implementation for editor tooling
+#define abs(x) (x)
+#define labs(x) (x)
 #endif
 
 long strtol(const char* restrict nptr, char** restrict endptr, int base);
diff --git a/src/system/CourseMap.hpp b/src/system/CourseMap.hpp
index d02748fe..c1e90153 100644
--- a/src/system/CourseMap.hpp
+++ b/src/system/CourseMap.hpp
@@ -453,9 +453,11 @@ class MapdataAreaAccessor {
   MapdataAreaBase** byPriority;
 };
 static_assert(sizeof(MapdataAreaAccessor) == 0x14);
+#ifndef __EDITOR_CHECKING__
 // Ensure the vtable does not exist at offset 0x0
 // (It should exist at offset 0x8)
 static_assert(offsetof(MapdataAreaAccessor, entries) == 0x0);
+#endif
 
 class MapdataCameraAccessor
     : public MapdataAccessorBase<MapdataCamera, MapdataCamera::SData> {