[libc] Move fileno and fdopen to fullbuild only (#128762)

Both fileno and fdopen require interfacing with the opaque FILE struct,
so they shouldn't be enabled in overlay mode. This patch moves both into
fullbuild only on all platforms.

Fixes #128643

Author: michaelrj-google

libc/config/linux/aarch64/entrypoints.txt

@@ -212,8 +212,6 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.realloc
 
     # stdio.h entrypoints
-    libc.src.stdio.fdopen
-    libc.src.stdio.fileno
     libc.src.stdio.fprintf
     libc.src.stdio.fscanf
     libc.src.stdio.vfscanf
@@ -918,6 +916,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.stdio.clearerr
     libc.src.stdio.clearerr_unlocked
     libc.src.stdio.fclose
+    libc.src.stdio.fdopen
     libc.src.stdio.feof
     libc.src.stdio.feof_unlocked
     libc.src.stdio.ferror
@@ -926,6 +925,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.stdio.fgetc
     libc.src.stdio.fgetc_unlocked
     libc.src.stdio.fgets
+    libc.src.stdio.fileno
     libc.src.stdio.flockfile
     libc.src.stdio.fopen
     libc.src.stdio.fopencookie

libc/config/linux/riscv/entrypoints.txt

@@ -211,8 +211,6 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.realloc
 
     # stdio.h entrypoints
-    libc.src.stdio.fdopen
-    libc.src.stdio.fileno
     libc.src.stdio.fprintf
     libc.src.stdio.fscanf
     libc.src.stdio.vfscanf
@@ -857,6 +855,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.stdio.clearerr
     libc.src.stdio.clearerr_unlocked
     libc.src.stdio.fclose
+    libc.src.stdio.fdopen
     libc.src.stdio.feof
     libc.src.stdio.feof_unlocked
     libc.src.stdio.ferror
@@ -865,6 +864,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.stdio.fgetc
     libc.src.stdio.fgetc_unlocked
     libc.src.stdio.fgets
+    libc.src.stdio.fileno
     libc.src.stdio.flockfile
     libc.src.stdio.fopen
     libc.src.stdio.fopencookie

libc/config/linux/x86_64/entrypoints.txt

@@ -211,8 +211,6 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.realloc
 
     # stdio.h entrypoints
-    libc.src.stdio.fdopen
-    libc.src.stdio.fileno
     libc.src.stdio.fprintf
     libc.src.stdio.fscanf
     libc.src.stdio.vfscanf
@@ -1018,6 +1016,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.stdio.clearerr
     libc.src.stdio.clearerr_unlocked
     libc.src.stdio.fclose
+    libc.src.stdio.fdopen
     libc.src.stdio.feof
     libc.src.stdio.feof_unlocked
     libc.src.stdio.ferror
@@ -1026,6 +1025,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.stdio.fgetc
     libc.src.stdio.fgetc_unlocked
     libc.src.stdio.fgets
+    libc.src.stdio.fileno
     libc.src.stdio.flockfile
     libc.src.stdio.fopen
     libc.src.stdio.fopencookie

libc/src/stdio/generic/fileno.cpp

@@ -1,5 +1,4 @@
-//===-- Implementation of fileno
-//-------------------------------------------===//
+//===-- Implementation of fileno ------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.