Cleanup CMake code (Windows-specific)

Prepare for a more modern CMake version than the current minimum.

- Use CMAKE_MSVC_RUNTIME_LIBRARY instead of the custom MSVC_CRT_TYPE.
- Replace CMAKE_{C,CXX}_FLAGS modifications with
  add_compile_definitions/options and add_link_options.
  The older method already broke with new pcre2.
- Fix clang-cl compilation and ASAN build.
- Avoid modifying CMAKE_C_STANDARD_LIBRARIES/CMAKE_CXX_STANDARD_LIBRARIES,
  as this is discouraged by CMake.
- Reduce system checks.

Author: vaintroub

CMakeLists.txt

@@ -31,7 +31,7 @@ ENDIF()
 # in RPM's:
 
 #set(CPACK_RPM_SPEC_MORE_DEFINE "%define __spec_install_post /bin/true")
-FOREACH(p CMP0022 CMP0046 CMP0040 CMP0048 CMP0054 CMP0056 CMP0067 CMP0074 CMP0075 CMP0069 CMP0135)
+FOREACH(p CMP0022 CMP0046 CMP0040 CMP0048 CMP0054 CMP0056 CMP0067 CMP0074 CMP0075 CMP0069 CMP0135 CMP0091)
   IF(POLICY ${p})
     CMAKE_POLICY(SET ${p} NEW)
   ENDIF()