0029266: Configuration - CMake install does not copy pdb files in Debug mode due to the changes in 0028287

Define variable "OCCT_INSTALL_BIN_LETTER" only if compiler is some version of Microsoft Visual C.

adm/cmake/occt_macros.cmake

@@ -585,7 +585,7 @@ endmacro()
 # prior to version 3.3 not supporting per-configuration install paths
 # for install target files (see https://cmake.org/Bug/view.php?id=14317)
 macro (OCCT_UPDATE_TARGET_FILE)
-  if (WIN32)
+  if (MSVC)
     OCCT_INSERT_CODE_FOR_TARGET ()
   endif()
 

adm/cmake/occt_toolkit.cmake

@@ -191,7 +191,7 @@ foreach (OCCT_MODULE ${OCC_MODULES_LIST})
   endif()
 endforeach()
 
-if (WIN32)
+if (MSVC)
   OCCT_INSERT_CODE_FOR_TARGET ()
 endif()