basic/include: trivial cleanups for libc header wrapper (#37937)

src/basic/include/malloc.h

@@ -3,8 +3,6 @@
 
 #include_next <malloc.h>
 
-#include "macro.h"
-
 #if !HAVE_MALLINFO2
 struct mallinfo2 {
         size_t arena;    /* non-mmapped space allocated from system */
@@ -20,9 +18,10 @@ struct mallinfo2 {
 };
 
 static inline struct mallinfo2 mallinfo2(void) {
-DISABLE_WARNING_DEPRECATED_DECLARATIONS
+        _Pragma("GCC diagnostic push");
+        _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"");
         struct mallinfo m = mallinfo();
-REENABLE_WARNING
+        _Pragma("GCC diagnostic pop");
 
         return (struct mallinfo2) {
                 .arena = m.arena,

src/basic/include/sys/mount.h

@@ -13,6 +13,12 @@
 #include "missing_fcntl.h"
 #include "missing_syscall_def.h"
 
+/* Since glibc-2.37 (774058d72942249f71d74e7f2b639f77184160a6), sys/mount.h includes linux/mount.h, and
+ * we can safely include both headers in the same source file. However, we cannot do that with older glibc.
+ * To avoid conflicts, let's not use glibc's sys/mount.h, and provide our own minimal implementation.
+ * Fortunately, most of definitions we need are covered by linux/fs.h and linux/mount.h, so only one enum
+ * and a few function prototypes need to be defined here. */
+
 /* Possible value for FLAGS parameter of `umount2'.  */
 enum
 {