diff --git a/Help/command/target_precompile_headers.rst b/Help/command/target_precompile_headers.rst
index 569c7eb..0d4f45a 100644
--- a/Help/command/target_precompile_headers.rst
+++ b/Help/command/target_precompile_headers.rst
@@ -56,35 +56,34 @@
 must be available for the compiler to find them.  Other header file names
 (e.g. ``project_header.h``) are interpreted as being relative to the current
 source directory (e.g. :variable:`CMAKE_CURRENT_SOURCE_DIR`) and will be
-included by absolute path.
-
-Arguments to ``target_precompile_headers()`` may use "generator expressions"
-with the syntax ``$<...>``.
-See the :manual:`cmake-generator-expressions(7)` manual for available
-expressions.  See the :manual:`cmake-compile-features(7)` manual for
-information on compile features and a list of supported compilers.
-The ``$<COMPILE_LANGUAGE:...>`` generator expression is particularly
-useful for specifying a language-specific header to precompile for
-only one language (e.g. ``CXX`` and not ``C``).  For example:
+included by absolute path.  For example:
 
 .. code-block:: cmake
 
   target_precompile_headers(myTarget
     PUBLIC
       project_header.h
-      "$<$<COMPILE_LANGUAGE:CXX>:cxx_only.h>"
     PRIVATE
       [["other_header.h"]]
       <unordered_map>
   )
 
-When specifying angle brackets inside a :manual:`generator expression
-<cmake-generator-expressions(7)>`, be sure to encode the closing ``>``
-as ``$<ANGLE-R>``.  For example:
+Arguments to ``target_precompile_headers()`` may use "generator expressions"
+with the syntax ``$<...>``.
+See the :manual:`cmake-generator-expressions(7)` manual for available
+expressions.
+The ``$<COMPILE_LANGUAGE:...>`` generator expression is particularly
+useful for specifying a language-specific header to precompile for
+only one language (e.g. ``CXX`` and not ``C``).  In this case, header
+file names that are not explicitly in double quotes or angle brackets
+must be specified by absolute path.  Also, when specifying angle brackets
+inside a generator expression, be sure to encode the closing ``>`` as
+``$<ANGLE-R>``.  For example:
 
 .. code-block:: cmake
 
   target_precompile_headers(mylib PRIVATE
+    "$<$<COMPILE_LANGUAGE:CXX>:${CMAKE_CURRENT_SOURCE_DIR}/cxx_only.h>"
     "$<$<COMPILE_LANGUAGE:C>:<stddef.h$<ANGLE-R>>"
     "$<$<COMPILE_LANGUAGE:CXX>:<cstddef$<ANGLE-R>>"
   )
diff --git a/Help/envvar/OBJC.rst b/Help/envvar/OBJC.rst
new file mode 100644
index 0000000..30c0d13
--- /dev/null
+++ b/Help/envvar/OBJC.rst
@@ -0,0 +1,14 @@
+OBJC
+----
+
+.. include:: ENV_VAR.txt
+
+Preferred executable for compiling ``OBJC`` language files. Will only be used
+by CMake on the first configuration to determine ``OBJC`` compiler, after
+which the value for ``OBJC`` is stored in the cache as
+:variable:`CMAKE_OBJC_COMPILER <CMAKE_<LANG>_COMPILER>`. For any configuration
+run (including the first), the environment variable will be ignored if the
+:variable:`CMAKE_OBJC_COMPILER <CMAKE_<LANG>_COMPILER>` variable is defined.
+
+If ``OBJC`` is not defined, the :envvar:`CC` environment variable will
+be checked instead.
diff --git a/Help/envvar/OBJCXX.rst b/Help/envvar/OBJCXX.rst
new file mode 100644
index 0000000..a72f7e7
--- /dev/null
+++ b/Help/envvar/OBJCXX.rst
@@ -0,0 +1,14 @@
+OBJCXX
+------
+
+.. include:: ENV_VAR.txt
+
+Preferred executable for compiling ``OBJCXX`` language files. Will only be used
+by CMake on the first configuration to determine ``OBJCXX`` compiler, after
+which the value for ``OBJCXX`` is stored in the cache as
+:variable:`CMAKE_OBJCXX_COMPILER <CMAKE_<LANG>_COMPILER>`. For any configuration
+run (including the first), the environment variable will be ignored if the
+:variable:`CMAKE_OBJCXX_COMPILER <CMAKE_<LANG>_COMPILER>` variable is defined.
+
+If ``OBJCXX`` is not defined, the :envvar:`CXX` environment variable will
+be checked instead.
diff --git a/Help/manual/cmake-env-variables.7.rst b/Help/manual/cmake-env-variables.7.rst
index 96ceb94..ec2c85d 100644
--- a/Help/manual/cmake-env-variables.7.rst
+++ b/Help/manual/cmake-env-variables.7.rst
@@ -54,6 +54,8 @@
    /envvar/CXXFLAGS
    /envvar/FC
    /envvar/FFLAGS
+   /envvar/OBJC
+   /envvar/OBJCXX
    /envvar/RC
    /envvar/RCFLAGS
    /envvar/SWIFTC
diff --git a/Help/release/3.16.rst b/Help/release/3.16.rst
index e2d6788..f3fdb08 100644
--- a/Help/release/3.16.rst
+++ b/Help/release/3.16.rst
@@ -303,3 +303,16 @@
   Additionally, the modules no longer expose their internal ``_Python*``
   cache entries publicly.  CMake 3.16.0 through 3.16.4 accidentally
   made them visible as advanced cache entries.
+
+3.16.7
+------
+
+* Selection of the Objective C or C++ compiler now considers the
+  :envvar:`CC` or :envvar:`CXX` environment variable if the
+  :envvar:`OBJC` or :envvar:`OBJCXX` environment variable is not set.
+
+* The :module:`FindPkgConfig` module now extracts include directories
+  prefixed with ``-isystem`` into the ``*_INCLUDE_DIRS`` variables and
+  :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` target properties.
+  Previously they would be places in ``*_CFLAGS_OTHER`` variables and
+  :prop_tgt:`INTERFACE_COMPILE_OPTIONS` target properties.
diff --git a/Modules/CMakeDetermineOBJCCompiler.cmake b/Modules/CMakeDetermineOBJCCompiler.cmake
index ad13eab..11b47fd 100644
--- a/Modules/CMakeDetermineOBJCCompiler.cmake
+++ b/Modules/CMakeDetermineOBJCCompiler.cmake
@@ -34,16 +34,19 @@
   if(NOT CMAKE_OBJC_COMPILER)
     set(CMAKE_OBJC_COMPILER_INIT NOTFOUND)
 
-    # prefer the environment variable OBJC
-    if($ENV{OBJC} MATCHES ".+")
-      get_filename_component(CMAKE_OBJC_COMPILER_INIT $ENV{OBJC} PROGRAM PROGRAM_ARGS CMAKE_OBJC_FLAGS_ENV_INIT)
-      if(CMAKE_OBJC_FLAGS_ENV_INIT)
-        set(CMAKE_OBJC_COMPILER_ARG1 "${CMAKE_OBJC_FLAGS_ENV_INIT}" CACHE STRING "First argument to Objective-C compiler")
+    # prefer the environment variable OBJC or CC
+    foreach(var OBJC CC)
+      if($ENV{${var}} MATCHES ".+")
+        get_filename_component(CMAKE_OBJC_COMPILER_INIT $ENV{${var}} PROGRAM PROGRAM_ARGS CMAKE_OBJC_FLAGS_ENV_INIT)
+        if(CMAKE_OBJC_FLAGS_ENV_INIT)
+          set(CMAKE_OBJC_COMPILER_ARG1 "${CMAKE_OBJC_FLAGS_ENV_INIT}" CACHE STRING "First argument to Objective-C compiler")
+        endif()
+        if(NOT EXISTS ${CMAKE_OBJC_COMPILER_INIT})
+          message(FATAL_ERROR "Could not find compiler set in environment variable ${var}:\n  $ENV{${var}}")
+        endif()
+        break()
       endif()
-      if(NOT EXISTS ${CMAKE_OBJC_COMPILER_INIT})
-        message(FATAL_ERROR "Could not find compiler set in environment variable OBJC:\n$ENV{OBJC}.")
-      endif()
-    endif()
+    endforeach()
 
     # next try prefer the compiler specified by the generator
     if(CMAKE_GENERATOR_OBJC)
diff --git a/Modules/CMakeDetermineOBJCXXCompiler.cmake b/Modules/CMakeDetermineOBJCXXCompiler.cmake
index 60fcbb3..db874d1 100644
--- a/Modules/CMakeDetermineOBJCXXCompiler.cmake
+++ b/Modules/CMakeDetermineOBJCXXCompiler.cmake
@@ -36,16 +36,19 @@
   if(NOT CMAKE_OBJCXX_COMPILER)
     set(CMAKE_OBJCXX_COMPILER_INIT NOTFOUND)
 
-    # prefer the environment variable OBJCXX
-    if($ENV{OBJCXX} MATCHES ".+")
-      get_filename_component(CMAKE_OBJCXX_COMPILER_INIT $ENV{OBJCXX} PROGRAM PROGRAM_ARGS CMAKE_OBJCXX_FLAGS_ENV_INIT)
-      if(CMAKE_OBJCXX_FLAGS_ENV_INIT)
-        set(CMAKE_OBJCXX_COMPILER_ARG1 "${CMAKE_OBJCXX_FLAGS_ENV_INIT}" CACHE STRING "First argument to Objective-C++ compiler")
+    # prefer the environment variable OBJCXX or CXX
+    foreach(var OBJCXX CXX)
+      if($ENV{${var}} MATCHES ".+")
+        get_filename_component(CMAKE_OBJCXX_COMPILER_INIT $ENV{${var}} PROGRAM PROGRAM_ARGS CMAKE_OBJCXX_FLAGS_ENV_INIT)
+        if(CMAKE_OBJCXX_FLAGS_ENV_INIT)
+          set(CMAKE_OBJCXX_COMPILER_ARG1 "${CMAKE_OBJCXX_FLAGS_ENV_INIT}" CACHE STRING "First argument to Objective-C++ compiler")
+        endif()
+        if(NOT EXISTS ${CMAKE_OBJCXX_COMPILER_INIT})
+          message(FATAL_ERROR "Could not find compiler set in environment variable ${var}:\n  $ENV{${var}}")
+        endif()
+        break()
       endif()
-      if(NOT EXISTS ${CMAKE_OBJCXX_COMPILER_INIT})
-        message(FATAL_ERROR "Could not find compiler set in environment variable OBJCXX:\n$ENV{OBJCXX}.\n${CMAKE_OBJCXX_COMPILER_INIT}")
-      endif()
-    endif()
+    endforeach()
 
     # next prefer the generator specified compiler
     if(CMAKE_GENERATOR_OBJCXX)
diff --git a/Modules/CheckLanguage.cmake b/Modules/CheckLanguage.cmake
index a1a3a7a..95e4fbe 100644
--- a/Modules/CheckLanguage.cmake
+++ b/Modules/CheckLanguage.cmake
@@ -43,7 +43,7 @@
     file(REMOVE_RECURSE ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/Check${lang})
 
     set(extra_compiler_variables)
-    if(lang STREQUAL CUDA)
+    if(${lang} STREQUAL CUDA)
       set(extra_compiler_variables "set(CMAKE_CUDA_HOST_COMPILER \\\"\${CMAKE_CUDA_HOST_COMPILER}\\\")")
     endif()
 
diff --git a/Modules/FindGTK2.cmake b/Modules/FindGTK2.cmake
index 83091f3..600e4aa 100644
--- a/Modules/FindGTK2.cmake
+++ b/Modules/FindGTK2.cmake
@@ -708,11 +708,14 @@
         _GTK2_FIND_LIBRARY    (CAIRO cairo false false)
         _GTK2_ADD_TARGET      (CAIRO)
 
+        _GTK2_FIND_INCLUDE_DIR(HARFBUZZ hb.h)
+        _GTK2_FIND_LIBRARY    (HARFBUZZ harfbuzz false false)
+        _GTK2_ADD_TARGET      (HARFBUZZ)
+
         _GTK2_FIND_INCLUDE_DIR(PANGO pango/pango.h)
         _GTK2_FIND_LIBRARY    (PANGO pango false true)
-        _GTK2_ADD_TARGET      (PANGO GTK2_DEPENDS gobject glib)
-
-        _GTK2_FIND_INCLUDE_DIR(HARFBUZZ hb.h)
+        _GTK2_ADD_TARGET      (PANGO GTK2_DEPENDS gobject glib
+                                     GTK2_OPTIONAL_DEPENDS harfbuzz)
 
         _GTK2_FIND_LIBRARY    (PANGOCAIRO pangocairo false true)
         _GTK2_ADD_TARGET      (PANGOCAIRO GTK2_DEPENDS pango cairo gobject glib)
diff --git a/Modules/FindMPI.cmake b/Modules/FindMPI.cmake
index d6cd799..42941c9 100644
--- a/Modules/FindMPI.cmake
+++ b/Modules/FindMPI.cmake
@@ -298,9 +298,9 @@
 endif()
 
 # PGI compiler names
-set(_MPI_PGI_C_COMPILER_NAMES              mpipgcc mppgcc)
-set(_MPI_PGI_CXX_COMPILER_NAMES            mpipgCC mppgCC)
-set(_MPI_PGI_Fortran_COMPILER_NAMES        mpipgf95 mpipgf90 mppgf95 mppgf90 mpipgf77 mppgf77)
+set(_MPI_PGI_C_COMPILER_NAMES              mpipgicc mpipgcc mppgcc)
+set(_MPI_PGI_CXX_COMPILER_NAMES            mpipgic++ mpipgCC mppgCC)
+set(_MPI_PGI_Fortran_COMPILER_NAMES        mpipgifort mpipgf95 mpipgf90 mppgf95 mppgf90 mpipgf77 mppgf77)
 
 # XLC MPI Compiler names
 set(_MPI_XL_C_COMPILER_NAMES               mpxlc      mpxlc_r    mpixlc     mpixlc_r)
diff --git a/Modules/FindPkgConfig.cmake b/Modules/FindPkgConfig.cmake
index bd1bc7c..2121f66 100644
--- a/Modules/FindPkgConfig.cmake
+++ b/Modules/FindPkgConfig.cmake
@@ -364,6 +364,36 @@
   unset(_pkgconfig_path_old)
 endmacro()
 
+# pkg-config returns -isystem include directories in --cflags-only-other,
+# depending on the version and if there is a space between -isystem and
+# the actual path
+function(_pkgconfig_extract_isystem _prefix)
+  set(cflags "${${_prefix}_CFLAGS_OTHER}")
+  set(outflags "")
+  set(incdirs "${${_prefix}_INCLUDE_DIRS}")
+
+  set(next_is_isystem FALSE)
+  foreach (THING IN LISTS cflags)
+    # This may filter "-isystem -isystem". That would not work anyway,
+    # so let it happen.
+    if (THING STREQUAL "-isystem")
+      set(next_is_isystem TRUE)
+      continue()
+    endif ()
+    if (next_is_isystem)
+      set(next_is_isystem FALSE)
+      list(APPEND incdirs "${THING}")
+    elseif (THING MATCHES "^-isystem")
+      string(SUBSTRING "${THING}" 8 -1 THING)
+      list(APPEND incdirs "${THING}")
+    else ()
+      list(APPEND outflags "${THING}")
+    endif ()
+  endforeach ()
+  set(${_prefix}_CFLAGS_OTHER "${outflags}" PARENT_SCOPE)
+  set(${_prefix}_INCLUDE_DIRS "${incdirs}" PARENT_SCOPE)
+endfunction()
+
 ###
 macro(_pkg_check_modules_internal _is_required _is_silent _no_cmake_path _no_cmake_environment_path _imp_target _imp_target_global _prefix)
   _pkgconfig_unset(${_prefix}_FOUND)
@@ -497,14 +527,18 @@
       endforeach()
 
       # set variables which are combined for multiple modules
-      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" LIBRARIES           "(^| )-l" --libs-only-l )
-      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" LIBRARY_DIRS        "(^| )-L" --libs-only-L )
-      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" LDFLAGS             ""        --libs )
-      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" LDFLAGS_OTHER       ""        --libs-only-other )
+      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" LIBRARIES     "(^| )-l"             --libs-only-l )
+      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" LIBRARY_DIRS  "(^| )-L"             --libs-only-L )
+      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" LDFLAGS       ""                    --libs )
+      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" LDFLAGS_OTHER ""                    --libs-only-other )
 
-      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" INCLUDE_DIRS        "(^| )-I" --cflags-only-I )
-      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" CFLAGS              ""        --cflags )
-      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" CFLAGS_OTHER        ""        --cflags-only-other )
+      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" INCLUDE_DIRS  "(^| )(-I|-isystem ?)" --cflags-only-I )
+      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" CFLAGS        ""                    --cflags )
+      _pkgconfig_invoke_dyn("${_pkg_check_modules_packages}" "${_prefix}" CFLAGS_OTHER  ""                    --cflags-only-other )
+
+      if (${_prefix}_CFLAGS_OTHER MATCHES "-isystem")
+        _pkgconfig_extract_isystem("${_prefix}")
+      endif ()
 
       _pkg_recalculate("${_prefix}" ${_no_cmake_path} ${_no_cmake_environment_path} ${_imp_target} ${_imp_target_global})
     endif()
diff --git a/Modules/Platform/Windows-MSVC.cmake b/Modules/Platform/Windows-MSVC.cmake
index 34f5d03..e0f33bd 100644
--- a/Modules/Platform/Windows-MSVC.cmake
+++ b/Modules/Platform/Windows-MSVC.cmake
@@ -331,13 +331,11 @@
 
   set(CMAKE_PCH_EXTENSION .pch)
   set(CMAKE_LINK_PCH ON)
-  if(MSVC_VERSION GREATER_EQUAL 1910)
-    # VS 2017 or greater
-    if (NOT ${CMAKE_${lang}_COMPILER_ID} STREQUAL "Clang")
-        set(CMAKE_PCH_PROLOGUE "#pragma system_header")
-    else()
-        set(CMAKE_PCH_PROLOGUE "#pragma clang system_header")
-    endif()
+  if (CMAKE_${lang}_COMPILER_ID STREQUAL "Clang")
+    set(CMAKE_PCH_PROLOGUE "#pragma clang system_header")
+  elseif(MSVC_VERSION GREATER_EQUAL 1913)
+    # At least MSVC toolet 14.13 from VS 2017 15.6
+    set(CMAKE_PCH_PROLOGUE "#pragma system_header")
   endif()
   if (NOT ${CMAKE_${lang}_COMPILER_ID} STREQUAL "Clang")
     set(CMAKE_PCH_COPY_COMPILE_PDB ON)
diff --git a/Source/CMakeVersion.cmake b/Source/CMakeVersion.cmake
index 93a8b85..0ec3463 100644
--- a/Source/CMakeVersion.cmake
+++ b/Source/CMakeVersion.cmake
@@ -1,7 +1,7 @@
 # CMake version number components.
 set(CMake_VERSION_MAJOR 3)
 set(CMake_VERSION_MINOR 16)
-set(CMake_VERSION_PATCH 6)
+set(CMake_VERSION_PATCH 7)
 #set(CMake_VERSION_RC 0)
 set(CMake_VERSION_IS_DIRTY 0)
 
diff --git a/Source/cmGlobalVisualStudioGenerator.cxx b/Source/cmGlobalVisualStudioGenerator.cxx
index ed0cba7..c083a75 100644
--- a/Source/cmGlobalVisualStudioGenerator.cxx
+++ b/Source/cmGlobalVisualStudioGenerator.cxx
@@ -111,6 +111,7 @@
 {
   char utf8bom[] = { char(0xEF), char(0xBB), char(0xBF) };
   fout.write(utf8bom, 3);
+  fout << '\n';
 
   switch (this->Version) {
     case cmGlobalVisualStudioGenerator::VS9:
diff --git a/Source/cmLocalUnixMakefileGenerator3.cxx b/Source/cmLocalUnixMakefileGenerator3.cxx
index 919fb74..6f2183d 100644
--- a/Source/cmLocalUnixMakefileGenerator3.cxx
+++ b/Source/cmLocalUnixMakefileGenerator3.cxx
@@ -1457,7 +1457,7 @@
     // Create the scanner for this language
     std::unique_ptr<cmDepends> scanner;
     if (lang == "C" || lang == "CXX" || lang == "RC" || lang == "ASM" ||
-        lang == "CUDA") {
+        lang == "OBJC" || lang == "OBJCXX" || lang == "CUDA") {
       // TODO: Handle RC (resource files) dependencies correctly.
       scanner = cm::make_unique<cmDependsC>(this, targetDir, lang, &validDeps);
     }
diff --git a/Source/cmMakefileTargetGenerator.cxx b/Source/cmMakefileTargetGenerator.cxx
index dd8a389..9d08e07 100644
--- a/Source/cmMakefileTargetGenerator.cxx
+++ b/Source/cmMakefileTargetGenerator.cxx
@@ -666,8 +666,9 @@
   // At the moment, it is assumed that C, C++, Fortran, and CUDA have both
   // assembly and preprocessor capabilities. The same is true for the
   // ability to export compile commands
-  bool lang_has_preprocessor = ((lang == "C") || (lang == "CXX") ||
-                                (lang == "Fortran") || (lang == "CUDA"));
+  bool lang_has_preprocessor =
+    ((lang == "C") || (lang == "CXX") || (lang == "OBJC") ||
+     (lang == "OBJCXX") || (lang == "Fortran") || (lang == "CUDA"));
   bool const lang_has_assembly = lang_has_preprocessor;
   bool const lang_can_export_cmds = lang_has_preprocessor;
 
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 80986fc..cdfd349 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -235,8 +235,11 @@
     !impl->Makefile->GetSafeDefinition("CMAKE_IMPORT_LIBRARY_SUFFIX").empty();
 
   // Check whether we are targeting AIX.
-  impl->IsAIX =
-    (impl->Makefile->GetSafeDefinition("CMAKE_SYSTEM_NAME") == "AIX");
+  {
+    std::string const& systemName =
+      impl->Makefile->GetSafeDefinition("CMAKE_SYSTEM_NAME");
+    impl->IsAIX = (systemName == "AIX" || systemName == "OS400");
+  }
 
   // Check whether we are targeting an Android platform.
   impl->IsAndroid =
diff --git a/Source/cmVisualStudio10TargetGenerator.cxx b/Source/cmVisualStudio10TargetGenerator.cxx
index f220ea5..b33cb50 100644
--- a/Source/cmVisualStudio10TargetGenerator.cxx
+++ b/Source/cmVisualStudio10TargetGenerator.cxx
@@ -2345,7 +2345,7 @@
         pchOptions =
           this->GeneratorTarget->GetPchUseCompileOptions(config, lang);
       }
-      customAndPchOptions += pchOptions;
+      customAndPchOptions = cmStrCat(customAndPchOptions, ';', pchOptions);
     }
 
     // if we have flags or defines for this config then
diff --git a/Tests/CMakeOnly/CheckLanguage/CMakeLists.txt b/Tests/CMakeOnly/CheckLanguage/CMakeLists.txt
index 90aa921..1570c37 100644
--- a/Tests/CMakeOnly/CheckLanguage/CMakeLists.txt
+++ b/Tests/CMakeOnly/CheckLanguage/CMakeLists.txt
@@ -18,16 +18,16 @@
   list(APPEND LANGUAGES OBJC OBJCXX)
 endif()
 
-foreach(lang ${LANGUAGES})
-  check_language(${lang})
-  if(NOT DEFINED CMAKE_${lang}_COMPILER)
-    message(FATAL_ERROR "check_language(${lang}) did not set result")
+foreach(test_lang ${LANGUAGES})
+  check_language(${test_lang})
+  if(NOT DEFINED CMAKE_${test_lang}_COMPILER)
+    message(FATAL_ERROR "check_language(${test_lang}) did not set result")
   endif()
-  if(DEFINED expect_${lang})
-    if(expect_${lang} AND NOT CMAKE_${lang}_COMPILER)
-      message(FATAL_ERROR "check_language(${lang}) should not fail!")
-    elseif(NOT expect_${lang} AND CMAKE_${lang}_COMPILER)
-      message(FATAL_ERROR "check_language(${lang}) should not succeed!")
+  if(DEFINED expect_${test_lang})
+    if(expect_${test_lang} AND NOT CMAKE_${test_lang}_COMPILER)
+      message(FATAL_ERROR "check_language(${test_lang}) should not fail!")
+    elseif(NOT expect_${test_lang} AND CMAKE_${test_lang}_COMPILER)
+      message(FATAL_ERROR "check_language(${test_lang}) should not succeed!")
     endif()
   endif()
 endforeach()
diff --git a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_IMPORTED_TARGET.cmake b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_IMPORTED_TARGET.cmake
index 62bb5de..d697fc6 100644
--- a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_IMPORTED_TARGET.cmake
+++ b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_IMPORTED_TARGET.cmake
@@ -99,6 +99,7 @@
 Description: Dummy package for FindPkgConfig IMPORTED_TARGET INTERFACE_LINK_OPTIONS test
 Version: 1.2.3
 Libs: -e dummy_main
+Cflags: -I/special -isystem /other -isystem/more -DA-isystem/foo
 ")
 
 set(expected_link_options -e dummy_main)
@@ -109,7 +110,26 @@
 get_target_property(link_options PkgConfig::FakeLinkOptionsPackage INTERFACE_LINK_OPTIONS)
 if (NOT link_options STREQUAL expected_link_options)
   message(FATAL_ERROR
-    "Additional link options not present in INTERFACE_LINK_OPTIONS property"
+    "Additional link options not present in INTERFACE_LINK_OPTIONS property\n"
     "expected: \"${expected_link_options}\", but got \"${link_options}\""
   )
 endif()
+
+get_target_property(inc_dirs PkgConfig::FakeLinkOptionsPackage INTERFACE_INCLUDE_DIRECTORIES)
+set(expected_inc_dirs "/special" "/other" "/more")
+
+if (NOT inc_dirs STREQUAL expected_inc_dirs)
+  message(FATAL_ERROR
+    "Additional include directories not correctly present in INTERFACE_INCLUDE_DIRECTORIES property\n"
+    "expected: \"${expected_inc_dirs}\", got \"${inc_dirs}\""
+  )
+endif ()
+
+get_target_property(c_opts PkgConfig::FakeLinkOptionsPackage INTERFACE_COMPILE_OPTIONS)
+set(expected_c_opts "-DA-isystem/foo") # this is an invalid option, but a good testcase
+if (NOT c_opts STREQUAL expected_c_opts)
+    message(FATAL_ERROR
+      "Additional compile options not present in INTERFACE_COMPILE_OPTIONS property\n"
+      "expected: \"${expected_c_opts}\", got \"${c_opts}\""
+    )
+endif ()
diff --git a/Tests/RunCMake/PrecompileHeaders/PchInterface.cmake b/Tests/RunCMake/PrecompileHeaders/PchInterface.cmake
index a1e0792..aab20d8 100644
--- a/Tests/RunCMake/PrecompileHeaders/PchInterface.cmake
+++ b/Tests/RunCMake/PrecompileHeaders/PchInterface.cmake
@@ -9,6 +9,9 @@
   <stdio.h>
   \"string.h\"
 )
+if(CMAKE_C_COMPILER_ID STREQUAL "MSVC")
+  set_property(SOURCE foo.c APPEND PROPERTY COMPILE_OPTIONS "-WX-")
+endif()
 
 add_library(bar INTERFACE)
 target_include_directories(bar INTERFACE include)
diff --git a/Tests/RunCMake/PrecompileHeaders/PchMultilanguage-check.cmake b/Tests/RunCMake/PrecompileHeaders/PchMultilanguage-check.cmake
index cc01ecb..9714bea 100644
--- a/Tests/RunCMake/PrecompileHeaders/PchMultilanguage-check.cmake
+++ b/Tests/RunCMake/PrecompileHeaders/PchMultilanguage-check.cmake
@@ -13,14 +13,14 @@
 
 file(STRINGS ${foobar_pch_h_header} foobar_pch_h_header_strings)
 
-if (NOT foobar_pch_h_header_strings MATCHES ";#include <stddef.h>(;|$)")
+if (NOT foobar_pch_h_header_strings MATCHES ";#include \"[^\"]*PrecompileHeaders/include/foo_C.h\";#include <stddef.h>(;|$)")
   set(RunCMake_TEST_FAILED "Generated foo pch header\n  ${foobar_pch_h_header}\nhas bad content:\n  ${foobar_pch_h_header_strings}")
   return()
 endif()
 
 file(STRINGS ${foobar_pch_hxx_header} foobar_pch_hxx_header_strings)
 
-if (NOT foobar_pch_hxx_header_strings MATCHES ";#include <cstddef>(;|$)")
+if (NOT foobar_pch_hxx_header_strings MATCHES ";#include \"[^\"]*PrecompileHeaders/include/foo_CXX.h\";#include <cstddef>(;|$)")
   set(RunCMake_TEST_FAILED "Generated foo pch header\n  ${foobar_pch_hxx_header}\nhas bad content:\n  ${foobar_pch_hxx_header_strings}")
   return()
 endif()
diff --git a/Tests/RunCMake/PrecompileHeaders/PchMultilanguage.cmake b/Tests/RunCMake/PrecompileHeaders/PchMultilanguage.cmake
index cdc42b2..bb18a64 100644
--- a/Tests/RunCMake/PrecompileHeaders/PchMultilanguage.cmake
+++ b/Tests/RunCMake/PrecompileHeaders/PchMultilanguage.cmake
@@ -7,6 +7,8 @@
 )
 target_include_directories(foobar PUBLIC include)
 target_precompile_headers(foobar PRIVATE
+  "$<$<COMPILE_LANGUAGE:C>:${CMAKE_CURRENT_SOURCE_DIR}/include/foo_C.h>"
+  "$<$<COMPILE_LANGUAGE:CXX>:${CMAKE_CURRENT_SOURCE_DIR}/include/foo_CXX.h>"
   "$<$<COMPILE_LANGUAGE:C>:<stddef.h$<ANGLE-R>>"
   "$<$<COMPILE_LANGUAGE:CXX>:<cstddef$<ANGLE-R>>"
   )
diff --git a/Tests/RunCMake/PrecompileHeaders/include/foo_C.h b/Tests/RunCMake/PrecompileHeaders/include/foo_C.h
new file mode 100644
index 0000000..f4de601
--- /dev/null
+++ b/Tests/RunCMake/PrecompileHeaders/include/foo_C.h
@@ -0,0 +1 @@
+#include "foo.h"
diff --git a/Tests/RunCMake/PrecompileHeaders/include/foo_CXX.h b/Tests/RunCMake/PrecompileHeaders/include/foo_CXX.h
new file mode 100644
index 0000000..f4de601
--- /dev/null
+++ b/Tests/RunCMake/PrecompileHeaders/include/foo_CXX.h
@@ -0,0 +1 @@
+#include "foo.h"