Small include cleanup

src/catch2/internal/catch_enforce.hpp

@@ -12,6 +12,8 @@
 #include <catch2/internal/catch_compiler_capabilities.hpp>
 #include <catch2/internal/catch_reusable_string_stream.hpp>
 
+#include <exception> // for `std::exception` in no-exception configuration
+
 namespace Catch {
 #if !defined(CATCH_CONFIG_DISABLE_EXCEPTIONS)
     template <typename Ex>

src/catch2/internal/catch_is_permutation.hpp

@@ -9,6 +9,7 @@
 #define CATCH_IS_PERMUTATION_HPP_INCLUDED
 
 #include <iterator>
+#include <type_traits>
 
 namespace Catch {
     namespace Detail {

src/catch2/internal/catch_istream.hpp

@@ -12,8 +12,6 @@
 #include <catch2/internal/catch_unique_ptr.hpp>
 
 #include <iosfwd>
-#include <cstddef>
-#include <ostream>
 #include <string>
 
 namespace Catch {

src/catch2/matchers/catch_matchers_contains.hpp

@@ -12,6 +12,7 @@
 #include <catch2/internal/catch_move_and_forward.hpp>
 
 #include <functional>
+#include <type_traits>
 
 namespace Catch {
     namespace Matchers {

src/catch2/matchers/catch_matchers_range_equals.hpp

@@ -11,6 +11,8 @@
 #include <catch2/internal/catch_is_permutation.hpp>
 #include <catch2/matchers/catch_matchers_templated.hpp>
 
+#include <functional>
+
 namespace Catch {
     namespace Matchers {