Fix name of static library when targeting MinGW. (#1579)

Co-authored-by: Jordan Bayles <[email protected]>

Author: mmuetzel

Diff for: src/lib_json/CMakeLists.txt

@@ -143,7 +143,7 @@ if(BUILD_STATIC_LIBS)
 
     # avoid name clashes on windows as the shared import lib is also named jsoncpp.lib
     if(NOT DEFINED STATIC_SUFFIX AND BUILD_SHARED_LIBS)
-        if (WIN32)
+        if (MSVC OR ("${CMAKE_C_SIMULATE_ID}" STREQUAL "MSVC"))
             set(STATIC_SUFFIX "_static")
         else()
             set(STATIC_SUFFIX "")