diff --git a/src/if_mzsch.h b/src/if_mzsch.h
index 952b084..6f5cd33 100644
--- a/src/if_mzsch.h
+++ b/src/if_mzsch.h
@@ -5,17 +5,17 @@
 #ifndef _IF_MZSCH_H_
 #define _IF_MZSCH_H_
 #ifdef __MINGW32__
-/* Hack to engage Cygwin-specific settings */
+// Hack to engage Cygwin-specific settings
 # define __CYGWIN32__
 # include <stdint.h>
 #endif
 
 #ifdef PROTO
-/* avoid syntax error for defining Thread_Local_Variables. */
-# define __thread /* empty */
+// avoid syntax error for defining Thread_Local_Variables.
+# define __thread // empty
 #endif
 
-/* #ifdef needed for "make depend" */
+// #ifdef needed for "make depend"
 #ifdef FEAT_MZSCHEME
 # include <schvers.h>
 # include <scheme.h>
@@ -29,12 +29,12 @@
 # define SCHEME_STRINGP(obj) (SCHEME_BYTE_STRINGP(obj) || SCHEME_CHAR_STRINGP(obj))
 # define BYTE_STRING_VALUE(obj) ((char_u *)SCHEME_BYTE_STR_VAL(obj))
 #else
-/* macros for compatibility with older versions */
+// macros for compatibility with older versions
 # define scheme_current_config() scheme_config
 # define scheme_make_sized_byte_string scheme_make_sized_string
 # define scheme_format_utf8 scheme_format
 # ifndef DYNAMIC_MZSCHEME
-/* for dynamic MzScheme there will be separate definitions in if_mzsch.c */
+// for dynamic MzScheme there will be separate definitions in if_mzsch.c
 #  define scheme_get_sized_byte_string_output scheme_get_sized_string_output
 #  define scheme_make_byte_string scheme_make_string
 #  define scheme_make_byte_string_output_port scheme_make_string_output_port
@@ -46,21 +46,21 @@
 # define SCHEME_BYTE_STRINGP SCHEME_STRINGP
 #endif
 
-/* Precise GC macros */
+// Precise GC macros
 #ifndef MZ_GC_DECL_REG
-# define MZ_GC_DECL_REG(size)		 /* empty */
+# define MZ_GC_DECL_REG(size)		 // empty
 #endif
 #ifndef MZ_GC_VAR_IN_REG
-# define MZ_GC_VAR_IN_REG(x, v)		 /* empty */
+# define MZ_GC_VAR_IN_REG(x, v)		 // empty
 #endif
 #ifndef MZ_GC_ARRAY_VAR_IN_REG
-# define MZ_GC_ARRAY_VAR_IN_REG(x, v, l) /* empty */
+# define MZ_GC_ARRAY_VAR_IN_REG(x, v, l) // empty
 #endif
 #ifndef MZ_GC_REG
-# define MZ_GC_REG()			 /* empty */
+# define MZ_GC_REG()			 // empty
 #endif
 #ifndef MZ_GC_UNREG
-# define MZ_GC_UNREG()			 /* empty */
+# define MZ_GC_UNREG()			 // empty
 #endif
 
 #ifdef MZSCHEME_FORCE_GC
@@ -70,7 +70,7 @@
  */
 # define MZ_GC_CHECK() scheme_collect_garbage();
 #else
-# define MZ_GC_CHECK()			/* empty */
+# define MZ_GC_CHECK()			// empty
 #endif
 
-#endif /* _IF_MZSCH_H_ */
+#endif // _IF_MZSCH_H_