[libc++] Only include the system <stdint.h> and <locale.h> if they exist

[ldionne]

Prior to aa7f377, we only did an #include_next of those system headers if they existed. After removing those headers from libc++, we started assuming that the system provided the headers because we unconditionally started including them. This patch fixes that.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Louis Dionne (ldionne)

Changes

Prior to aa7f377, we only did an #include_next of those system headers if they existed. After removing those headers from libc++, we started assuming that the system provided the headers because we unconditionally started including them. This patch fixes that.

---

Full diff: https://github.com/llvm/llvm-project/pull/115017.diff

2 Files Affected:

• (modified) libcxx/include/clocale (+3-1)
• (modified) libcxx/include/cstdint (+3-1)

diff --git a/libcxx/include/clocale b/libcxx/include/clocale
index 4d53aa7eb29b29..a82a166712c26e 100644
--- a/libcxx/include/clocale
+++ b/libcxx/include/clocale
@@ -36,7 +36,9 @@ lconv* localeconv();
 
 #include <__config>
 
-#include <locale.h>
+#if __has_include(<locale.h>)
+#  include <locale.h>
+#endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/cstdint b/libcxx/include/cstdint
index 9c9b2323d06ea9..b3167c33f24778 100644
--- a/libcxx/include/cstdint
+++ b/libcxx/include/cstdint
@@ -142,7 +142,9 @@ Types:
 
 #include <__config>
 
-#include <stdint.h>
+#if __has_include(<stdint.h>)
+#  include <stdint.h>
+#endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header