diff --git a/include/zephyr/toolchain/llvm.h b/include/zephyr/toolchain/llvm.h
index 8a78d4e8404..a77e82a45e2 100644
--- a/include/zephyr/toolchain/llvm.h
+++ b/include/zephyr/toolchain/llvm.h
@@ -34,80 +34,42 @@
 #define __INT8_C(x)	x
 #endif
 
-#ifndef INT8_C
-#define INT8_C(x)	__INT8_C(x)
-#endif
-
 #ifndef __UINT8_C
 #define __UINT8_C(x)	x ## U
 #endif
 
-#ifndef UINT8_C
-#define UINT8_C(x)	__UINT8_C(x)
-#endif
-
 #ifndef __INT16_C
 #define __INT16_C(x)	x
 #endif
 
-#ifndef INT16_C
-#define INT16_C(x)	__INT16_C(x)
-#endif
-
 #ifndef __UINT16_C
 #define __UINT16_C(x)	x ## U
 #endif
 
-#ifndef UINT16_C
-#define UINT16_C(x)	__UINT16_C(x)
-#endif
-
 #ifndef __INT32_C
 #define __INT32_C(x)	x
 #endif
 
-#ifndef INT32_C
-#define INT32_C(x)	__INT32_C(x)
-#endif
-
 #ifndef __UINT32_C
 #define __UINT32_C(x)	x ## U
 #endif
 
-#ifndef UINT32_C
-#define UINT32_C(x)	__UINT32_C(x)
-#endif
-
 #ifndef __INT64_C
 #define __INT64_C(x)	x
 #endif
 
-#ifndef INT64_C
-#define INT64_C(x)	__INT64_C(x)
-#endif
-
 #ifndef __UINT64_C
 #define __UINT64_C(x)	x ## ULL
 #endif
 
-#ifndef UINT64_C
-#define UINT64_C(x)	__UINT64_C(x)
-#endif
-
 #ifndef __INTMAX_C
 #define __INTMAX_C(x)	x
 #endif
 
-#ifndef INTMAX_C
-#define INTMAX_C(x)	__INTMAX_C(x)
-#endif
 
 #ifndef __UINTMAX_C
 #define __UINTMAX_C(x)	x ## ULL
 #endif
 
-#ifndef UINTMAX_C
-#define UINTMAX_C(x)	__UINTMAX_C(x)
-#endif
 
 #endif /* ZEPHYR_INCLUDE_TOOLCHAIN_LLVM_H_ */
diff --git a/lib/libc/minimal/include/stdint.h b/lib/libc/minimal/include/stdint.h
index 904f0b49b25..80a2ff1ab29 100644
--- a/lib/libc/minimal/include/stdint.h
+++ b/lib/libc/minimal/include/stdint.h
@@ -104,7 +104,7 @@ typedef __UINT_LEAST64_TYPE__	uint_least64_t;
 typedef __INTPTR_TYPE__		intptr_t;
 typedef __UINTPTR_TYPE__	uintptr_t;
 
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(__clang__)
 /* These macros must produce constant integer expressions, which can't
  * be done in the preprocessor (casts aren't allowed).  Defer to the
  * GCC internal functions where they're available.
@@ -120,7 +120,7 @@ typedef __UINTPTR_TYPE__	uintptr_t;
 #define UINT32_C(_v) __UINT32_C(_v)
 #define UINT64_C(_v) __UINT64_C(_v)
 #define UINTMAX_C(_v) __UINTMAX_C(_v)
-#endif /* __GNUC__ */
+#endif /* defined(__GNUC__) || defined(__clang__) */
 
 #ifdef __CCAC__
 #ifndef __INT8_C