Added platform unknown test

test/core/CMakeLists.txt

@@ -41,4 +41,5 @@ glmCreateTestGTC(core_func_swizzle)
 glmCreateTestGTC(core_setup_force_cxx98)
 glmCreateTestGTC(core_setup_force_size_t_length)
 glmCreateTestGTC(core_setup_message)
+glmCreateTestGTC(core_setup_platform_unknown)
 glmCreateTestGTC(core_setup_precision)

test/core/core_setup_platform_unknown.cpp

@@ -0,0 +1,10 @@
+#define GLM_FORCE_PLATFORM_UNKNOWN
+#include <glm/glm.hpp>
+#include <glm/ext.hpp>
+
+int main()
+{
+	int Error = 0;
+
+	return Error;
+}