diff --git a/Source/cmDependsJavaLexer.cxx b/Source/cmDependsJavaLexer.cxx
index 503fb2808a..5951418b69 100644
--- a/Source/cmDependsJavaLexer.cxx
+++ b/Source/cmDependsJavaLexer.cxx
@@ -704,7 +704,9 @@ Modify cmDependsJavaLexer.h:
 #if defined( _WIN32 ) && !defined( __CYGWIN__ )
 /* Handle Windows properly */
 #  include <io.h>
-#  define isatty _isatty
+#  if defined( _MSC_VER )
+#    define isatty _isatty
+#  endif
 #  define YY_NO_UNISTD_H 1
 #endif
 
diff --git a/Source/cmDependsJavaLexer.in.l b/Source/cmDependsJavaLexer.in.l
index f77f7fd8b9..4eab54ebe9 100644
--- a/Source/cmDependsJavaLexer.in.l
+++ b/Source/cmDependsJavaLexer.in.l
@@ -67,7 +67,9 @@ Modify cmDependsJavaLexer.h:
 #if defined( _WIN32 ) && !defined( __CYGWIN__ )
 /* Handle Windows properly */
 #  include <io.h>
-#  define isatty _isatty
+#  if defined( _MSC_VER )
+#    define isatty _isatty
+#  endif
 #  define YY_NO_UNISTD_H 1
 #endif