Sync known vc++ versions in 7.1

Author: weltling

win32/build/confutils.js

@@ -70,6 +70,8 @@ VC_VERSIONS[1700] = 'MSVC11 (Visual C++ 2012)';
 VC_VERSIONS[1800] = 'MSVC12 (Visual C++ 2013)';
 VC_VERSIONS[1900] = 'MSVC14 (Visual C++ 2015)';
 VC_VERSIONS[1910] = 'MSVC15 (Visual C++ 2017)';
+VC_VERSIONS[1911] = 'MSVC15 (Visual C++ 2017)';
+VC_VERSIONS[1912] = 'MSVC15 (Visual C++ 2017)';
 
 var VC_VERSIONS_SHORT = new Array();
 VC_VERSIONS_SHORT[1200] = 'VC6';
@@ -82,6 +84,8 @@ VC_VERSIONS_SHORT[1700] = 'VC11';
 VC_VERSIONS_SHORT[1800] = 'VC12';
 VC_VERSIONS_SHORT[1900] = 'VC14';
 VC_VERSIONS_SHORT[1910] = 'VC15';
+VC_VERSIONS_SHORT[1911] = 'VC15';
+VC_VERSIONS_SHORT[1912] = 'VC15';
 
 if (PROGRAM_FILES == null) {
 	PROGRAM_FILES = "C:\\Program Files";