From 7dc184fbeb550c8710a7b25a1462968c7bfed92a Mon Sep 17 00:00:00 2001
From: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Date: Thu, 5 May 2022 22:30:48 +0300
Subject: Use constant for array size in os-linux

When cross-compiling for Linux on Windows using VC toolchain
(in dotnet/runtime), we get the following error:
> error C2057: expected constant expression

This is because VC runtime does not support VLAs

The fix is to use a C constant.
---
 src/os-linux.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/os-linux.c b/src/os-linux.c
index e212fd59..1f57736f 100644
--- a/src/os-linux.c
+++ b/src/os-linux.c
@@ -33,6 +33,8 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 #include "libunwind_i.h"
 #include "os-linux.h"
 
+#define FULL_PATH_BUFF_SZ 1024
+
 int
 tdep_get_elf_image (struct elf_image *ei, pid_t pid, unw_word_t ip,
                     unsigned long *segbase, unsigned long *mapoff,
@@ -44,8 +46,7 @@ tdep_get_elf_image (struct elf_image *ei, pid_t pid, unw_word_t ip,
   char root[sizeof ("/proc/0123456789/root")], *cp;
   char *full_path;
   struct stat st;
-  const unsigned long full_path_buff_sz = 1024;
-  char                full_path_buff[full_path_buff_sz];
+  char                full_path_buff[FULL_PATH_BUFF_SZ];
 
   if (maps_init (&mi, pid) < 0)
     return -1;
@@ -74,13 +75,13 @@ tdep_get_elf_image (struct elf_image *ei, pid_t pid, unw_word_t ip,
   if (!stat(root, &st) && S_ISDIR(st.st_mode))
     {
       unsigned long _len = strlen(root) + strlen(mi.path) + 1;
-      if(_len >= full_path_buff_sz)
+      if(_len >= FULL_PATH_BUFF_SZ)
         {
           full_path = (char*) malloc(_len);
         }
       else
         {
-          snprintf(full_path_buff, full_path_buff_sz, "%s%s", root, mi.path);
+          snprintf(full_path_buff, FULL_PATH_BUFF_SZ, "%s%s", root, mi.path);
           full_path = &full_path_buff[0];
         }
       if (!full_path)
-- 
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