MSYS: fix CMake configure and build for MinGW

cMake/FreeCAD_Helpers/ConfigureCMakeVariables.cmake

@@ -2,7 +2,7 @@ macro(ConfigureCMakeVariables)
     # ================================================================================
     # Output directories for install target
 
-    if(WIN32)
+    if(MSVC)
         set(CMAKE_INSTALL_PREFIX ${CMAKE_BINARY_DIR}/install CACHE PATH "Installation root directory")
         set(CMAKE_INSTALL_BINDIR bin CACHE PATH "Output directory for executables")
         set(CMAKE_INSTALL_DATADIR data CACHE PATH "Output directory for data and resource files")

cMake/FreeCAD_Helpers/SetupSalomeSMESH.cmake

@@ -75,7 +75,7 @@ macro(SetupSalomeSMESH)
         if(NOT FREECAD_USE_EXTERNAL_SMESH)
             find_package(MEDFile REQUIRED)
             # See https://www.hdfgroup.org/HDF5/release/cmakebuild.html
-            if (WIN32)
+            if (MSVC)
                 find_package(HDF5 COMPONENTS NO_MODULE REQUIRED static)
             else()
                 find_package(PkgConfig)