diff --git a/lib/curl_setup.h b/lib/curl_setup.h
index 0d4a8fa577..312df9d9c3 100644
--- a/lib/curl_setup.h
+++ b/lib/curl_setup.h
@@ -1578,7 +1578,7 @@ typedef struct sockaddr_un {
 /* The code is compiled with C++ compiler.
    C++ always supports 'inline'. */
 #  define CURL_INLINE inline /* 'inline' keyword supported */
-#elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901
+#elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
 /* C99 (and later) supports 'inline' keyword */
 #  define CURL_INLINE inline /* 'inline' keyword supported */
 #elif defined(__GNUC__) && __GNUC__ >= 3
diff --git a/lib/curl_sha512_256.c b/lib/curl_sha512_256.c
index 5c3bcdf800..02baf88f4d 100644
--- a/lib/curl_sha512_256.c
+++ b/lib/curl_sha512_256.c
@@ -301,7 +301,7 @@ static CURLcode Curl_sha512_256_finish(unsigned char *digest, void *context)
 
 #ifdef __GNUC__
 #  if defined(__has_attribute) && defined(__STDC_VERSION__)
-#    if __has_attribute(always_inline) && __STDC_VERSION__ >= 199901
+#    if __has_attribute(always_inline) && __STDC_VERSION__ >= 199901L
 #      define CURL_FORCEINLINE CURL_INLINE __attribute__((always_inline))
 #    endif
 #  endif