diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0810c31b..bcb7cb23 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -387,10 +387,6 @@ if(CRYPTO_BACKEND STREQUAL "mbedTLS" OR NOT CRYPTO_BACKEND)
     list(APPEND LIBRARIES ${MBEDTLS_LIBRARIES})
     list(APPEND LIBSSH2_PC_LIBS_PRIVATE "-lmbedcrypto")
     link_directories(${MBEDTLS_LIBRARY_DIR})
-
-    # mbedTLS (as of v3.5.1) has a duplicate function declaration
-    # in its own public headers. Disable the warning that detects it.
-    string(REGEX REPLACE "-Wredundant-decls" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
   endif()
 endif()
 
diff --git a/src/crypto.h b/src/crypto.h
index 8307d77f..145dc88f 100644
--- a/src/crypto.h
+++ b/src/crypto.h
@@ -46,7 +46,16 @@
 #elif defined(LIBSSH2_LIBGCRYPT)
 #include "libgcrypt.h"
 #elif defined(LIBSSH2_MBEDTLS)
+/* mbedTLS (as of v3.5.1) has a duplicate function declaration
+   in its own public headers. Disable the warning that detects it. */
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wredundant-decls"
+#endif
 #include "mbedtls.h"
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
 #elif defined(LIBSSH2_OS400QC3)
 #include "os400qc3.h"
 #elif defined(LIBSSH2_WINCNG)