From 371072e9e1677e883d3feed167b53e075fb129b3 Mon Sep 17 00:00:00 2001
From: Aiden Woodruff <aiden.woodruff@gmail.com>
Date: Sun, 12 Jul 2020 21:36:03 -0400
Subject: CheckTypeSize: Use C++-style headers to check for std:: types

In order to check for types like `std::uint8_t` in C++, we need to
include `<cstdint>` instead of `<stdint.h>`.
---
 Modules/CheckTypeSize.cmake | 54 ++++++++++++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 18 deletions(-)

diff --git a/Modules/CheckTypeSize.cmake b/Modules/CheckTypeSize.cmake
index 2b07b7c..17beadc 100644
--- a/Modules/CheckTypeSize.cmake
+++ b/Modules/CheckTypeSize.cmake
@@ -89,17 +89,38 @@ function(__check_type_size_impl type var map builtin language)
     message(CHECK_START "Check size of ${type}")
   endif()
 
+  # Perform language check
+  if(language STREQUAL "C")
+    set(src ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CheckTypeSize/${var}.c)
+  elseif(language STREQUAL "CXX")
+    set(src ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CheckTypeSize/${var}.cpp)
+  else()
+    message(FATAL_ERROR "Unknown language:\n  ${language}\nSupported languages: C, CXX.\n")
+  endif()
+
   # Include header files.
   set(headers)
   if(builtin)
-    if(HAVE_SYS_TYPES_H)
-      string(APPEND headers "#include <sys/types.h>\n")
-    endif()
-    if(HAVE_STDINT_H)
-      string(APPEND headers "#include <stdint.h>\n")
-    endif()
-    if(HAVE_STDDEF_H)
-      string(APPEND headers "#include <stddef.h>\n")
+    if(language STREQUAL "CXX" AND type MATCHES "^std::")
+      if(HAVE_SYS_TYPES_H)
+        string(APPEND headers "#include <sys/types.h>\n")
+      endif()
+      if(HAVE_CSTDINT)
+        string(APPEND headers "#include <cstdint>\n")
+      endif()
+      if(HAVE_CSTDDEF)
+        string(APPEND headers "#include <cstddef>\n")
+      endif()
+    else()
+      if(HAVE_SYS_TYPES_H)
+        string(APPEND headers "#include <sys/types.h>\n")
+      endif()
+      if(HAVE_STDINT_H)
+        string(APPEND headers "#include <stdint.h>\n")
+      endif()
+      if(HAVE_STDDEF_H)
+        string(APPEND headers "#include <stddef.h>\n")
+      endif()
     endif()
   endif()
   foreach(h ${CMAKE_EXTRA_INCLUDE_FILES})
@@ -107,14 +128,6 @@ function(__check_type_size_impl type var map builtin language)
   endforeach()
 
   # Perform the check.
-
-  if(language STREQUAL "C")
-    set(src ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CheckTypeSize/${var}.c)
-  elseif(language STREQUAL "CXX")
-    set(src ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CheckTypeSize/${var}.cpp)
-  else()
-    message(FATAL_ERROR "Unknown language:\n  ${language}\nSupported languages: C, CXX.\n")
-  endif()
   set(bin ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CheckTypeSize/${var}.bin)
   configure_file(${__check_type_size_dir}/CheckTypeSize.c.in ${src} @ONLY)
   try_compile(HAVE_${var} ${CMAKE_BINARY_DIR} ${src}
@@ -232,8 +245,13 @@ macro(CHECK_TYPE_SIZE TYPE VARIABLE)
       check_include_file(stddef.h HAVE_STDDEF_H)
     elseif(_language STREQUAL "CXX")
       check_include_file_cxx(sys/types.h HAVE_SYS_TYPES_H)
-      check_include_file_cxx(stdint.h HAVE_STDINT_H)
-      check_include_file_cxx(stddef.h HAVE_STDDEF_H)
+      if("${TYPE}" MATCHES "^std::")
+        check_include_file_cxx(cstdint HAVE_CSTDINT)
+        check_include_file_cxx(cstddef HAVE_CSTDDEF)
+      else()
+        check_include_file_cxx(stdint.h HAVE_STDINT_H)
+        check_include_file_cxx(stddef.h HAVE_STDDEF_H)
+      endif()
     endif()
   endif()
   unset(_CHECK_TYPE_SIZE_BUILTIN_TYPES_ONLY)
-- 
cgit v0.12