diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3fcde11..1acc0b5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -128,7 +128,7 @@ if(MSVC)
     # handle msvcrt setting being passed in CMAKE_C_FLAGS
     if(CMAKE_C_FLAGS MATCHES "[/-]M[TD]d?")
         # ensure CMAKE_MSVC_RUNTIME_LIBRARY is not already defined
-        if(DEFINED CMAKE_MSVC_RUNTIME_LIBRARY)
+        if(NOT CMAKE_MSVC_RUNTIME_LIBRARY)
             message(FATAL_ERROR "please set the runtime library via either CMAKE_C_FLAGS or CMAKE_MSVC_RUNTIME_LIBRARY, not both")
         endif()
 
@@ -1486,7 +1486,7 @@ if(UNICORN_BUILD_TESTS)
 endif()
 
 
-if(UNICORN_INSTALL AND NOT MSVC)
+if(UNICORN_INSTALL)
     include("GNUInstallDirs")
     file(GLOB UNICORN_HEADERS ${CMAKE_CURRENT_SOURCE_DIR}/include/unicorn/*.h)
     if (BUILD_SHARED_LIBS)