diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index c359011..1cd20fe 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -61,11 +61,6 @@
 /** Invalid input data. */
 #define MBEDTLS_ERR_AES_BAD_INPUT_DATA                    -0x0021
 
-#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
-    !defined(inline) && !defined(__cplusplus)
-#define inline __inline
-#endif
-
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/include/mbedtls/build_info.h b/include/mbedtls/build_info.h
index 170cbeb..362ce2f 100644
--- a/include/mbedtls/build_info.h
+++ b/include/mbedtls/build_info.h
@@ -53,6 +53,12 @@
 #define _CRT_SECURE_NO_DEPRECATE 1
 #endif
 
+/* Define `inline` on some non-C99-compliant compilers. */
+#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
+    !defined(inline) && !defined(__cplusplus)
+#define inline __inline
+#endif
+
 #if !defined(MBEDTLS_CONFIG_FILE)
 #include "mbedtls/mbedtls_config.h"
 #else
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index a3f52ea..151da1d 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -46,11 +46,6 @@
 #define MBEDTLS_CIPHER_MODE_STREAM
 #endif
 
-#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
-    !defined(inline) && !defined(__cplusplus)
-#define inline __inline
-#endif
-
 /** The selected feature is not available. */
 #define MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE  -0x6080
 /** Bad input parameters. */
diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index eb83913..04e0896 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -26,11 +26,6 @@
 
 #include <stddef.h>
 
-#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
-    !defined(inline) && !defined(__cplusplus)
-#define inline __inline
-#endif
-
 /**
  * Error code layout.
  *
diff --git a/include/mbedtls/pem.h b/include/mbedtls/pem.h
index c75a124..a4c6fb8 100644
--- a/include/mbedtls/pem.h
+++ b/include/mbedtls/pem.h
@@ -27,11 +27,6 @@
 
 #include <stddef.h>
 
-#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
-    !defined(inline) && !defined(__cplusplus)
-#define inline __inline
-#endif
-
 /**
  * \name PEM Error codes
  * These error codes are returned in case of errors reading the
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 867961d..db0bfac 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -44,11 +44,6 @@
 #include "psa/crypto.h"
 #endif
 
-#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
-    !defined(inline) && !defined(__cplusplus)
-#define inline __inline
-#endif
-
 /** Memory allocation failed. */
 #define MBEDTLS_ERR_PK_ALLOC_FAILED        -0x3F80
 /** Type mismatch, eg attempt to encrypt with an ECDSA key */