From 9916fc6f1f93f3e092e3c6937c30dc8137c26d34 Mon Sep 17 00:00:00 2001
From: Chen Qi <Qi.Chen@windriver.com>
Date: Thu, 15 Jun 2023 18:31:26 +0800
Subject: [PATCH] unix/configure: use _Static_assert to do correct detection

We're doing cross compilation, running a cross-compiled problem
on host to detemine feature is not correct. Use _Static_assert
to do the detection correctly.

Upstream-Status: Inactive-Upstream

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
 unix/configure | 42 ++++++++++++------------------------------
 1 file changed, 12 insertions(+), 30 deletions(-)

diff --git a/unix/configure b/unix/configure
index f2b3d02..f917086 100644
--- a/unix/configure
+++ b/unix/configure
@@ -361,6 +361,10 @@ cat > conftest.c << _EOF_
 #include <sys/stat.h>
 #include <unistd.h>
 #include <stdio.h>
+
+_Static_assert(sizeof((struct stat){0}.st_uid) == 2, "sizeof st_uid is not 16 bit");
+_Static_assert(sizeof((struct stat){0}.st_gid) == 2, "sizeof st_gid is not 16 bit");
+
 int main()
 {
   struct stat s;
@@ -385,21 +389,7 @@ if [ $? -ne 0 ]; then
   echo -- UID/GID test failed on compile - disabling old 16-bit UID/GID support
   CFLAGS="${CFLAGS} -DUIDGID_NOT_16BIT"
 else
-# run it
-  ./conftest
-  r=$?
-  if [ $r -eq 1 ]; then
-    echo -- UID not 2 bytes - disabling old 16-bit UID/GID support
-    CFLAGS="${CFLAGS} -DUIDGID_NOT_16BIT"
-  elif [ $r -eq 2 ]; then
-    echo -- GID not 2 bytes - disabling old 16-bit UID/GID support
-    CFLAGS="${CFLAGS} -DUIDGID_NOT_16BIT"
-  elif [ $r -eq 3 ]; then
-    echo -- 16-bit UIDs and GIDs - keeping old 16-bit UID/GID support
-  else
-    echo -- test failed - conftest returned $r - disabling old 16-bit UID/GID support
-    CFLAGS="${CFLAGS} -DUIDGID_NOT_16BIT"
-  fi
+  echo -- 16-bit UIDs and GIDs - keeping old 16-bit UID/GID support
 fi
 
 
@@ -417,6 +407,10 @@ cat > conftest.c << _EOF_
 #include <sys/stat.h>
 #include <unistd.h>
 #include <stdio.h>
+
+_Static_assert(sizeof(off_t) < 8, "sizeof off_t < 8 failed");
+_Static_assert(sizeof((struct stat){0}.st_size) < 8, "sizeof st_size < 8 failed");
+
 int main()
 {
   off_t offset;
@@ -436,24 +430,12 @@ _EOF_
 # compile it
 $CC -o conftest conftest.c >/dev/null 2>/dev/null
 if [ $? -ne 0 ]; then
-  echo -- no Large File Support
+  echo -- yes we have Large File Support!
+  CFLAGS="${CFLAGS} -DLARGE_FILE_SUPPORT"
 else
-# run it
-  ./conftest
-  r=$?
-  if [ $r -eq 1 ]; then
-    echo -- no Large File Support - no 64-bit off_t
-  elif [ $r -eq 2 ]; then
-    echo -- no Large File Support - no 64-bit stat
-  elif [ $r -eq 3 ]; then
-    echo -- yes we have Large File Support!
-    CFLAGS="${CFLAGS} -DLARGE_FILE_SUPPORT"
-  else
-    echo -- no Large File Support - conftest returned $r
-  fi
+  echo -- no Large File Support
 fi
 
-
 # Check for wide char for Unicode support
 # Added 11/24/2005 EG
 
-- 
2.34.1