Most changes from review comments implemented. Remove use of "#elif" for

backward PP compatability. Add BOOST_category_item_AVAILABLE as a
defined, or not, symbol for use with "#ifdef" or "#ifndef". Add
documentation of macros used for detection and version information. Also
replace direct use of BVN(0,0,0) and BVN(0,0,1) with more meaningful
macros that are globally defined, and hence consistent.

include/boost/predef/compiler/borland.h

@@ -28,17 +28,22 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_BORLAND BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_BORLAND BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__BORLANDC__) || defined(__CODEGEARC__)
 #   undef BOOST_COMP_BORLAND
-#   if defined(__CODEGEARC__)
+#   if !defined(BOOST_COMP_BORLAND) && (defined(__CODEGEARC__))
 #       define BOOST_COMP_BORLAND BOOST_PREDEF_MAKE_0X_VVRP(__CODEGEARC__)
-#   else
+#   endif
+#   if !defined(BOOST_COMP_BORLAND)
 #       define BOOST_COMP_BORLAND BOOST_PREDEF_MAKE_0X_VVRP(__BORLANDC__)
 #   endif
 #endif
 
+#if BOOST_COMP_BORLAND
+#   define BOOST_COMP_BORLAND_AVAILABLE
+#endif
+
 #define BOOST_COMP_BORLAND_NAME "Borland C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/clang.h

@@ -26,13 +26,17 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_CLANG BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_CLANG BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__clang__)
 #   undef BOOST_COMP_CLANG
 #   define BOOST_COMP_CLANG BOOST_VERSION_NUMBER(__clang_major__,__clang_minor__,__clang_patchlevel__)
 #endif
 
+#if BOOST_COMP_CLANG
+#   define BOOST_COMP_CLANG_AVAILABLE
+#endif
+
 #define BOOST_COMP_CLANG_NAME "Clang"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/comeau.h

@@ -11,7 +11,7 @@ http://www.boost.org/LICENSE_1_0.txt)
 #include <boost/predef/version_number.h>
 #include <boost/predef/make.h>
 
-#define BOOST_COMP_COMO BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_COMO BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 /*`
 [heading `BOOST_COMP_COMO`]
@@ -30,11 +30,16 @@ Version number available as major, minor, and patch.
 
 #if defined(__COMO__)
 #   undef BOOST_COMP_COMO
-#   if defined(__CONO_VERSION__)
+#   if !defined(BOOST_COMP_COMO) && defined(__CONO_VERSION__)
 #       define BOOST_COMP_COMO BOOST_PREDEF_MAKE_0X_VRP(__COMO_VERSION__)
-#   else
-#       define BOOST_COMP_COMO BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_COMO)
+#       define BOOST_COMP_COMO BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_COMO
+#   define BOOST_COMP_COMO_AVAILABLE
 #endif
 
 #define BOOST_COMP_COMO_NAME "Comeau C++"

include/boost/predef/compiler/compaq.h

@@ -28,17 +28,23 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_DEC BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_DEC BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__DECC) || defined(__DECCXX)
 #   undef BOOST_COMP_DEC
-#   if defined(__DECCXX_VER)
+#   if !defined(BOOST_COMP_DEC) && defined(__DECCXX_VER)
 #       define BOOST_COMP_DEC BOOST_PREDEF_MAKE_10_VVRR0PP00(__DECCXX_VER)
-#   elif defined(__DECC_VER)
-#       define BOOST_COMP_DEC BOOST_PREDEF_MAKE_10_VVRR0PP00(__DECC_VER)
-#   else
-#       define BOOST_COM_DEV BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_DEC) && defined(__DECC_VER)
+#       define BOOST_COMP_DEC BOOST_PREDEF_MAKE_10_VVRR0PP00(__DECC_VER)
+#   endif
+#   if !defined(BOOST_COMP_DEC)
+#       define BOOST_COM_DEV BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_DEC
+#   define BOOST_COMP_DEC_AVAILABLE
 #endif
 
 #define BOOST_COMP_DEC_NAME "Compaq C/C++"

include/boost/predef/compiler/diab.h

@@ -26,13 +26,17 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_DIAB BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_DIAB BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__DCC__)
 #   undef BOOST_COMP_DIAB
 #   define BOOST_COMP_DIAB BOOST_PREDEF_MAKE_10_VRPP(__VERSION_NUMBER__)
 #endif
 
+#if BOOST_COMP_DIAB
+#   define BOOST_COMP_DIAB_AVAILABLE
+#endif
+
 #define BOOST_COMP_DIAB_NAME "Diab C/C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/digitalmars.h

@@ -26,13 +26,17 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_DMC BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_DMC BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__DMC__)
 #   undef BOOST_COMP_DMC
 #   define BOOST_COMP_DMC BOOST_PREDEF_MAKE_0X_VRP(__DMC__)
 #endif
 
+#if BOOST_COMP_DMC
+#   define BOOST_COMP_DMC_AVAILABLE
+#endif
+
 #define BOOST_COMP_DMC_NAME "Digital Mars"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/dignus.h

@@ -26,13 +26,17 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_SYSC BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_SYSC BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__SYSC__)
 #   undef BOOST_COMP_SYSC
 #   define BOOST_COMP_SYSC BOOST_PREDEF_MAKE_10_VRRPP(__SYSC_VER__)
 #endif
 
+#if BOOST_COMP_SYSC
+#   define BOOST_COMP_SYSC_AVAILABLE
+#endif
+
 #define BOOST_COMP_SYSC_NAME "Dignus Systems/C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/edg.h

@@ -26,13 +26,17 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_EDG BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_EDG BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__EDG__)
 #   undef BOOST_COMP_EDG
 #   define BOOST_COMP_EDG BOOST_PREDEF_MAKE_10_VRR(__EDG_VERSION__)
 #endif
 
+#if BOOST_COMP_EDG
+#   define BOOST_COMP_EDG_AVAILABLE
+#endif
+
 #define BOOST_COMP_EDG_NAME "EDG C++ Frontend"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/ekopath.h

@@ -26,7 +26,7 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_PATH BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_PATH BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__PATHCC__)
 #   undef BOOST_COMP_PATH
@@ -34,6 +34,10 @@ Version number available as major, minor, and patch.
         BOOST_VERSION_NUMBER(__PATHCC__,__PATHCC_MINOR__,__PATHCC_PATCHLEVEL__)
 #endif
 
+#if BOOST_COMP_PATH
+#   define BOOST_COMP_PATH_AVAILABLE
+#endif
+
 #define BOOST_COMP_PATH_NAME "EKOpath"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/gcc.h

@@ -27,19 +27,24 @@ Version number available as major, minor, and patch (if available).
     ]
  */
 
-#define BOOST_COMP_GNUC BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_GNUC BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__GNUC__)
 #   undef BOOST_COMP_GNUC
-#   if defined(__GNUC_PATCHLEVEL__)
+#   if !defined(BOOST_COMP_GNUC) && defined(__GNUC_PATCHLEVEL__)
 #       define BOOST_COMP_GNUC \
             BOOST_VERSION_NUMBER(__GNUC__,__GNUC_MINOR__,__GNUC_PATCHLEVEL__)
-#   else
+#   endif
+#   if !defined(BOOST_COMP_GNUC)
 #       define BOOST_COMP_GNUC \
             BOOST_VERSION_NUMBER(__GNUC__,__GNUC_MINOR__,0)
 #   endif
 #endif
 
+#if BOOST_COMP_GNUC
+#   define BOOST_COMP_GNUC_AVAILABLE
+#endif
+
 #define BOOST_COMP_GNUC_NAME "Gnu GCC C/C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/gcc_xml.h

@@ -23,11 +23,15 @@ http://www.boost.org/LICENSE_1_0.txt)
     ]
  */
 
-#define BOOST_COMP_GCCXML BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_GCCXML BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__GCCXML__)
 #   undef BOOST_COMP_GCCXML
-#   define BOOST_COMP_GCCXML BOOST_VERSION_NUMBER(0,0,1)
+#   define BOOST_COMP_GCCXML BOOST_VERSION_NUMBER_AVAILABLE
+#endif
+
+#if BOOST_COMP_GCCXML
+#   define BOOST_COMP_GCCXML_AVAILABLE
 #endif
 
 #define BOOST_COMP_GCCXML_NAME "GCC XML"

include/boost/predef/compiler/greenhills.h

@@ -28,15 +28,23 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_GHS BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_GHS BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__ghs) || defined(__ghs__)
 #   undef BOOST_COMP_GHS
-#   if defined(__GHS_VERSION_NUMBER__)
+#   if !defined(BOOST_COMP_GHS) && defined(__GHS_VERSION_NUMBER__)
 #       define BOOST_COMP_GHS BOOST_PREDEF_MAKE_10_VRP(__GHS_VERSION_NUMBER__)
-#   else if defined(__ghs)
+#   endif
+#   if !defined(BOOST_COMP_GHS) && defined(__ghs)
 #       define BOOST_COMP_GHS BOOST_PREDEF_MAKE_10_VRP(__ghs)
 #   endif
+#   if !defined(BOOST_COMP_GHS)
+#       define BOOST_COMP_GHS BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_GHS
+#   define BOOST_COMP_GHS_AVAILABLE
 #endif
 
 #define BOOST_COMP_GHS_NAME "Green Hills C/C++"

include/boost/predef/compiler/hp_acc.h

@@ -26,15 +26,20 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_HPACC BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_HPACC BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__HP_aCC)
 #   undef BOOST_COMP_HPACC
-#   if (__HP_aCC > 1)
+#   if !defined(BOOST_COMP_HPACC) && (__HP_aCC > 1)
 #       define BOOST_COMP_HPACC BOOST_PREDEF_MAKE_10_VVRRPP(__HP_aCC)
-#   else
-#       define BOOST_COMP_HPACC BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_HPACC)
+#       define BOOST_COMP_HPACC BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_HPACC
+#   define BOOST_COMP_HPACC_AVAILABLE
 #endif
 
 #define BOOST_COMP_HPACC_NAME "HP aC++"

include/boost/predef/compiler/iar.h

@@ -26,13 +26,17 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_IAR BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_IAR BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__IAR_SYSTEMS_ICC__)
 #   undef BOOST_COMP_IAR
 #   define BOOST_COMP_IAR BOOST_PREDEF_MAKE_10_VVRR(__VER__)
 #endif
 
+#if BOOST_COMP_IAR
+#   define BOOST_COMP_IAR_AVAILABLE
+#endif
+
 #define BOOST_COMP_IAR_NAME "IAR C/C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/ibm.h

@@ -31,21 +31,28 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_IBM BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_IBM BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__IBMCPP__) || defined(__xlC__) || defined(__xlc__)
 #   undef BOOST_COMP_IBM
-#   if defined(__COMPILER_VER__)
+#   if !defined(BOOST_COMP_IBM) && defined(__COMPILER_VER__)
 #       define BOOST_COMP_IBM BOOST_PREDEF_MAKE_0X_VRRPPPP(__COMPILER_VER__)
-#   elif defined(__xlC__)
+#   endif
+#   if !defined(BOOST_COMP_IBM) && defined(__xlC__)
 #       define BOOST_COMP_IBM BOOST_PREDEF_MAKE_0X_VVRR(__xlC__)
-#   elif defined(__xlc__)
+#   endif
+#   if !defined(BOOST_COMP_IBM) && defined(__xlc__)
 #       define BOOST_COMP_IBM BOOST_PREDEF_MAKE_0X_VVRR(__xlc__)
-#   else
+#   endif
+#   if !defined(BOOST_COMP_IBM)
 #       define BOOST_COMP_IBM BOOST_PREDEF_MAKE_10_VRP(__IBMCPP__)
 #   endif
 #endif
 
+#if BOOST_COMP_IBM
+#   define BOOST_COMP_IBM_AVAILABLE
+#endif
+
 #define BOOST_COMP_IBM_NAME "IBM XL C/C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/intel.h

@@ -29,16 +29,21 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_INTEL BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_INTEL BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__INTEL_COMPILER) || defined(__ICL) || defined(__ICC) || \
     defined(__ECC)
 #   undef BOOST_COMP_INTEL
-#   if defined(__INTEL_COMPILER)
+#   if !defined(BOOST_COMP_INTEL) && defined(__INTEL_COMPILER)
 #       define BOOST_COMP_INTEL BOOST_PREDEF_MAKE_10_VRP(__INTEL_COMPILER)
-#   else
-#       define BOOST_COMP_INTEL BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_INTEL)
+#       define BOOST_COMP_INTEL BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_INTEL
+#   define BOOST_COMP_INTEL_AVAILABLE
 #endif
 
 #define BOOST_COMP_INTEL_NAME "Intel C/C++"

include/boost/predef/compiler/kai.h

@@ -26,13 +26,17 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_KCC BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_KCC BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__KCC)
 #   undef BOOST_COMP_KCC
 #   define BOOST_COMP_KCC BOOST_PREDEF_MAKE_0X_VRPP(__KCC_VERSION)
 #endif
 
+#if BOOST_COMP_KCC
+#   define BOOST_COMP_KCC_AVAILABLE
+#endif
+
 #define BOOST_COMP_KCC_NAME "Kai C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/llvm.h

@@ -23,11 +23,15 @@ http://www.boost.org/LICENSE_1_0.txt)
     ]
  */
 
-#define BOOST_COMP_LLVM BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_LLVM BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__llvm__)
 #   undef BOOST_COMP_LLVM
-#   define BOOST_COMP_LLVM BOOST_VERSION_NUMBER(0,0,1)
+#   define BOOST_COMP_LLVM BOOST_VERSION_NUMBER_AVAILABLE
+#endif
+
+#if BOOST_COMP_LLVM
+#   define BOOST_COMP_LLVM_AVAILABLE
 #endif
 
 #define BOOST_COMP_LLVM_NAME "LLVM"

include/boost/predef/compiler/metaware.h

@@ -23,11 +23,15 @@ MetaWare High C/C++ compiler.
     ]
  */
 
-#define BOOST_COMP_HIGHC BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_HIGHC BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__HIGHC__)
 #   undef BOOST_COMP_HIGHC
-#   define BOOST_COMP_HIGHC BOOST_VERSION_NUMBER(0,0,1)
+#   define BOOST_COMP_HIGHC BOOST_VERSION_NUMBER_AVAILABLE
+#endif
+
+#if BOOST_COMP_HIGHC
+#   define BOOST_COMP_HIGHC_AVAILABLE
 #endif
 
 #define BOOST_COMP_HIGHC_NAME "MetaWare High C/C++"

include/boost/predef/compiler/metrowerks.h

@@ -30,23 +30,32 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__MWERKS__) || defined(__CWCC__)
 #   undef BOOST_COMP_MWERKS
-#   if defined(__CWCC__)
+#   if !defined(BOOST_COMP_MWERKS) && defined(__CWCC__)
 #       define BOOST_COMP_MWERKS BOOST_PREDEF_MAKE_0X_VRPP(__CWCC__)
-#   elif (__MWERKS__ >= 0x4200)
-#       define BOOST_COMP_MWERKS BOOST_PREDEF_MAKE_0X_VRPP(__MWERKS__)
-#   elif (__MWERKS__ >= 0x3204) // note the "skip": 04->9.3
-#       define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER(9,(__MWERKS__)%100-1,0)
-#   elif (__MWERKS__ >= 0x3200)
-#       define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER(9,(__MWERKS__)%100,0)
-#   elif (__MWERKS__ >= 0x3000)
-#       define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER(8,(__MWERKS__)%100,0)
-#   else
-#       define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_MWERKS) && (__MWERKS__ >= 0x4200)
+#       define BOOST_COMP_MWERKS BOOST_PREDEF_MAKE_0X_VRPP(__MWERKS__)
+#   endif
+#   if !defined(BOOST_COMP_MWERKS) && (__MWERKS__ >= 0x3204) // note the "skip": 04->9.3
+#       define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER(9,(__MWERKS__)%100-1,0)
+#   endif
+#   if !defined(BOOST_COMP_MWERKS) && (__MWERKS__ >= 0x3200)
+#       define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER(9,(__MWERKS__)%100,0)
+#   endif
+#   if !defined(BOOST_COMP_MWERKS) && (__MWERKS__ >= 0x3000)
+#       define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER(8,(__MWERKS__)%100,0)
+#   endif
+#   if !defined(BOOST_COMP_MWERKS)
+#       define BOOST_COMP_MWERKS BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_MWERKS
+#   define BOOST_COMP_MWERKS_AVAILABLE
 #endif
 
 #define BOOST_COMP_MWERKS_NAME "Metrowerks CodeWarrior"

include/boost/predef/compiler/microtec.h

@@ -23,11 +23,15 @@ http://www.boost.org/LICENSE_1_0.txt)
     ]
  */
 
-#define BOOST_COMP_MRI BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_MRI BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(_MRI)
 #   undef BOOST_COMP_MRI
-#   define BOOST_COMP_MRI BOOST_VERSION_NUMBER(0,0,1)
+#   define BOOST_COMP_MRI BOOST_VERSION_NUMBER_AVAILABLE
+#endif
+
+#if BOOST_COMP_MRI
+#   define BOOST_COMP_MRI_AVAILABLE
 #endif
 
 #define BOOST_COMP_MRI_NAME "Microtec C/C++"

include/boost/predef/compiler/mingw.h

@@ -28,20 +28,26 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_MINGW BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_MINGW BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__MINGW32__) || defined(__MINGW64__)
 #   include <_mingw.h>
 #   undef BOOST_COMP_MINGW
-#   if defined(__MINGW64_VERSION_MAJOR) && defined(__MINGW64_VERSION_MINOR)
+#   if !defined(BOOST_COMP_MINGW) && (defined(__MINGW64_VERSION_MAJOR) && defined(__MINGW64_VERSION_MINOR))
 #       define BOOST_COMP_MINGW \
             BOOST_VERSION_NUMBER(__MINGW64_VERSION_MAJOR,__MINGW64_VERSION_MINOR,0)
-#   elif defined(__MINGW32_VERSION_MAJOR) && defined(__MINGW32_VERSION_MINOR)
+#   endif
+#   if !defined(BOOST_COMP_MINGW) && (defined(__MINGW32_VERSION_MAJOR) && defined(__MINGW32_VERSION_MINOR))
 #       define BOOST_COMP_MINGW \
             BOOST_VERSION_NUMBER(__MINGW32_MAJOR_VERSION,__MINGW32_MINOR_VERSION,0)
-#   else
-#       define BOOST_COMP_MINGW BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_MINGW)
+#       define BOOST_COMP_MINGW BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_MINGW
+#   define BOOST_COMP_MINGW_AVAILABLE
 #endif
 
 #define BOOST_COMP_MINGW_NAME "MinGW"

include/boost/predef/compiler/mpw.h

@@ -28,15 +28,20 @@ Version number available as major, and minor.
     ]
  */
 
-#define BOOST_COMP_MPW BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_MPW BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__MRC__) || defined(MPW_C) || defined(MPW_CPLUS)
 #   undef BOOST_COMP_MPW
-#   if defined(__MRC__)
+#   if !defined(BOOST_COMP_MPW) && defined(__MRC__)
 #       define BOOST_COMP_MPW BOOST_PREDEF_MAKE_0X_VVRR(__MRC__)
-#   else
-#       define BOOST_COMP_MPW BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_MPW)
+#       define BOOST_COMP_MPW BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_MPW
+#   define BOOST_COMP_MPW_AVAILABLE
 #endif
 
 #define BOOST_COMP_MPW_NAME "MPW C++"

include/boost/predef/compiler/palm.h

@@ -26,13 +26,17 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_PALM BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_PALM BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(_PACC_VER)
 #   undef BOOST_COMP_PALM
 #   define BOOST_COMP_PALM BOOST_PREDEF_MAKE_0X_VRRPP000(_PACC_VER)
 #endif
 
+#if BOOST_COMP_PALM
+#   define BOOST_COMP_PALM_AVAILABLE
+#endif
+
 #define BOOST_COMP_PALM_NAME "Palm C/C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/pgi.h

@@ -25,15 +25,20 @@ http://www.boost.org/LICENSE_1_0.txt)
     ]
  */
 
-#define BOOST_COMP_PGI BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_PGI BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__PGI)
 #   undef BOOST_COMP_PGI
-#   if defined(__PGIC__) && defined(__PGIC_MINOR__) && defined(__PGIC_PATCHLEVEL__)
+#   if !defined(BOOST_COMP_PGI) && (defined(__PGIC__) && defined(__PGIC_MINOR__) && defined(__PGIC_PATCHLEVEL__))
 #       define BOOST_COMP_PGI BOOST_VERSION_NUMBER(__PGIC__,__PGIC_MINOR__,__PGIC_PATCHLEVEL__)
-#   else
-#       define BOOST_COMP_PGI BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_PGI)
+#       define BOOST_COMP_PGI BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_PGI
+#   define BOOST_COMP_PGI_AVAILABLE
 #endif
 
 #define BOOST_COMP_PGI_NAME "Portland Group C/C++"

include/boost/predef/compiler/sgi_mipspro.h

@@ -28,17 +28,23 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_SGI BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_SGI BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__sgi) || defined(sgi)
 #   undef BOOST_COMP_SGI
-#   if defined(_SGI_COMPILER_VERSION)
+#   if !defined(BOOST_COMP_SGI) && defined(_SGI_COMPILER_VERSION)
 #       define BOOST_COMP_SGI BOOST_PREDEF_MAKE_10_VRP(_SGI_COMPILER_VERSION)
-#   elif defined(_COMPILER_VERSION)
-#       define BOOST_COMP_SGI BOOST_PREDEF_MAKE_10_VRP(_COMPILER_VERSION)
-#   else
-#       define BOOST_COMP_SGI BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_SGI) && defined(_COMPILER_VERSION)
+#       define BOOST_COMP_SGI BOOST_PREDEF_MAKE_10_VRP(_COMPILER_VERSION)
+#   endif
+#   if !defined(BOOST_COMP_SGI)
+#       define BOOST_COMP_SGI BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_SGI
+#   define BOOST_COMP_SGI_AVAILABLE
 #endif
 
 #define BOOST_COMP_SGI_NAME "SGI MIPSpro"

include/boost/predef/compiler/sunpro.h

@@ -28,17 +28,23 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_SUNPRO BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_SUNPRO BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__SUNPRO_CC) || defined(__SUNPRO_C)
 #   undef BOOST_COMP_SUNPRO
-#   if defined(__SUNPRO_CC)
+#   if !defined(BOOST_COMP_SUNPRO) && defined(__SUNPRO_CC)
 #       define BOOST_COMP_SUNPRO BOOST_PREDEF_MAKE_0X_VRP(__SUNPRO_CC)
-#   elif defined(__SUNPRO_C)
-#       define BOOST_COMP_SUNPRO BOOST_PREDEF_MAKE_0X_VRP(__SUNPRO_C)
-#   else
-#       define BOOST_COMP_SUNPRO BOOST_VERSION_NUMBER(0,0,1)
 #   endif
+#   if !defined(BOOST_COMP_SUNPRO) && defined(__SUNPRO_C)
+#       define BOOST_COMP_SUNPRO BOOST_PREDEF_MAKE_0X_VRP(__SUNPRO_C)
+#   endif
+#   if !defined(BOOST_COMP_SUNPRO)
+#       define BOOST_COMP_SUNPRO BOOST_VERSION_NUMBER_AVAILABLE
+#   endif
+#endif
+
+#if BOOST_COMP_SUNPRO
+#   define BOOST_COMP_SUNPRO_AVAILABLE
 #endif
 
 #define BOOST_COMP_SUNPRO_NAME "Sun Studio"

include/boost/predef/compiler/tendra.h

@@ -23,11 +23,15 @@ http://www.boost.org/LICENSE_1_0.txt)
     ]
  */
 
-#define BOOST_COMP_TENDRA BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_TENDRA BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__TenDRA__)
 #   undef BOOST_COMP_TENDRA
-#   define BOOST_COMP_TENDRA BOOST_VERSION_NUMBER(0,0,1)
+#   define BOOST_COMP_TENDRA BOOST_VERSION_NUMBER_AVAILABLE
+#endif
+
+#if BOOST_COMP_TENDRA
+#   define BOOST_COMP_TENDRA_AVAILABLE
 #endif
 
 #define BOOST_COMP_TENDRA_NAME "TenDRA C/C++"

include/boost/predef/compiler/visualc.h

@@ -27,7 +27,7 @@ Version number available as major, minor, and patch.
     ]
  */
 
-#define BOOST_COMP_MSVC BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_MSVC BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(_MSC_VER)
 #   undef BOOST_COMP_MSVC
@@ -51,6 +51,10 @@ Version number available as major, minor, and patch.
         BOOST_COMP_MSVC_BUILD)
 #endif
 
+#if BOOST_COMP_MSVC
+#   define BOOST_COMP_MSVC_AVAILABLE
+#endif
+
 #define BOOST_COMP_MSVC_NAME "Microsoft Visual C/C++"
 
 #include <boost/predef/detail/test.h>

include/boost/predef/compiler/watcom.h

@@ -26,13 +26,17 @@ Version number available as major, and minor.
     ]
  */
 
-#define BOOST_COMP_WATCOM BOOST_VERSION_NUMBER(0,0,0)
+#define BOOST_COMP_WATCOM BOOST_VERSION_NUMBER_NOT_AVAILABLE
 
 #if defined(__WATCOMC__)
 #   undef BOOST_COMP_WATCOM
 #   define BOOST_COMP_WATCOM BOOST_PREDEF_MAKE_10_VVRR(__WATCOMC__)
 #endif
 
+#if BOOST_COMP_WATCOM
+#   define BOOST_COMP_WATCOM_AVAILABLE
+#endif
+
 #define BOOST_COMP_WATCOM_NAME "Watcom C++"
 
 #include <boost/predef/detail/test.h>