diff --git a/CMakeLists.txt b/CMakeLists.txt
index 366ffc4..95318a0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -107,10 +107,9 @@ endif()
 
 # Compiler flags
 if(CMAKE_C_COMPILER_ID MATCHES "AppleClang|Clang|GNU")
-  list(APPEND mi_cflags -Wall -Wextra -Wno-unknown-pragmas)
+  list(APPEND mi_cflags -Wall -Wextra -Wno-unknown-pragmas -fvisibility=hidden)
   if(CMAKE_C_COMPILER_ID MATCHES "GNU")
     list(APPEND mi_cflags -Wno-invalid-memory-model)
-    list(APPEND mi_cflags -fvisibility=hidden)
   endif()
 endif()
 
diff --git a/include/mimalloc-internal.h b/include/mimalloc-internal.h
index eaa327b..88a0f86 100644
--- a/include/mimalloc-internal.h
+++ b/include/mimalloc-internal.h
@@ -23,7 +23,7 @@ terms of the MIT license. A copy of the license can be found in the file
 #if defined(_MSC_VER)
 #pragma warning(disable:4127)   // constant conditional due to MI_SECURE paths
 #define mi_decl_noinline   __declspec(noinline)
-#elif defined(__GNUC__) || defined(__clang__)
+#elif (defined(__GNUC__) && (__GNUC__>=3))  // includes clang and icc
 #define mi_decl_noinline   __attribute__((noinline))
 #else
 #define mi_decl_noinline
diff --git a/include/mimalloc.h b/include/mimalloc.h
index 1c77d46..7cf455e 100644
--- a/include/mimalloc.h
+++ b/include/mimalloc.h
@@ -43,7 +43,7 @@ terms of the MIT license. A copy of the license can be found in the file
   #define mi_attr_alloc_size(s)
   #define mi_attr_alloc_size2(s1,s2)
   #define mi_attr_alloc_align(p)
-#elif defined(__GNUC__) || defined(__clang__)
+#elif defined(__GNUC__)               // includes clang and icc
   #define mi_cdecl                    // leads to warnings... __attribute__((cdecl))
   #define mi_decl_thread              __thread
   #define mi_decl_export              __attribute__((visibility("default")))